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href="/zh-CN/docs/Learn/Getting_started_with_the_web/What_will_your_website_look_like">你的网站会是什么样子？</a></li><li><a href="/zh-CN/docs/Learn/Getting_started_with_the_web/Dealing_with_files">处理文件</a></li><li><a href="/zh-CN/docs/Learn/Getting_started_with_the_web/HTML_basics">HTML 基础</a></li><li><a href="/zh-CN/docs/Learn/Getting_started_with_the_web/CSS_basics">CSS 基础</a></li><li><a href="/zh-CN/docs/Learn/Getting_started_with_the_web/JavaScript_basics">JavaScript 基础</a></li><li><a href="/zh-CN/docs/Learn/Getting_started_with_the_web/Publishing_your_website">发布你的网站</a></li><li><a href="/zh-CN/docs/Learn/Getting_started_with_the_web/How_the_Web_works">万维网是如何工作的</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/HTML">HTML——构建 Web</a></li><li><details><summary>HTML 介绍</summary><ol><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML">HTML 简介</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Getting_started">开始学习 HTML</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/The_head_metadata_in_HTML">“头”里有什么——HTML 元信息</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/HTML_text_fundamentals">HTML 文本处理基础</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Creating_hyperlinks">创建超链接</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Advanced_text_formatting">文本格式进阶</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Document_and_website_structure">文档与网站架构</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Debugging_HTML">HTML 调试</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Marking_up_a_letter">标记信件</a></li><li><a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Structuring_a_page_of_content">构建网页内容</a></li></ol></details></li><li><details><summary>多媒体与嵌入</summary><ol><li><a href="/zh-CN/docs/Learn/HTML/Multimedia_and_embedding">多媒体与嵌入</a></li><li><a href="/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Images_in_HTML">HTML 中的图片</a></li><li><a href="/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Video_and_audio_content">视频和音频内容</a></li><li><a href="/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Other_embedding_technologies">从 object 到 iframe——其他嵌入技术</a></li><li><a href="/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Adding_vector_graphics_to_the_Web">向 web 中添加矢量图形</a></li><li><a href="/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images">响应式图片</a></li><li><a href="/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Mozilla_splash_page">Mozilla 欢迎页面</a></li></ol></details></li><li><details><summary>HTML 表格</summary><ol><li><a href="/zh-CN/docs/Learn/HTML/Tables">HTML 表格</a></li><li><a href="/zh-CN/docs/Learn/HTML/Tables/Basics">HTML 表格基础</a></li><li><a href="/zh-CN/docs/Learn/HTML/Tables/Advanced">HTML 表格进阶特性和无障碍</a></li><li><a href="/zh-CN/docs/Learn/HTML/Tables/Structuring_planet_data">作业：构建行星数据</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/CSS">CSS——设计 Web</a></li><li><details><summary>CSS 第一步</summary><ol><li><a href="/zh-CN/docs/Learn/CSS/First_steps">CSS 入门概述</a></li><li><a href="/zh-CN/docs/Learn/CSS/First_steps/What_is_CSS">什么是 CSS?</a></li><li><a href="/zh-CN/docs/Learn/CSS/First_steps/Getting_started">让我们开始 CSS 的学习之旅</a></li><li><a href="/zh-CN/docs/Learn/CSS/First_steps/How_CSS_is_structured">CSS 的组成</a></li><li><a href="/zh-CN/docs/Learn/CSS/First_steps/How_CSS_works">CSS 如何运行</a></li><li><a href="/zh-CN/docs/Learn/CSS/First_steps/Styling_a_biography_page">运用你的新知识</a></li></ol></details></li><li><details><summary>CSS 基础</summary><ol><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks">CSS 构建</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Selectors">CSS 选择器</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Selectors/Type_Class_and_ID_Selectors">类型、类和 ID 选择器</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Selectors/Attribute_selectors">属性选择器</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Selectors/Pseudo-classes_and_pseudo-elements">伪类和伪元素</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Selectors/Combinators">关系选择器</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Cascade_and_inheritance">层叠、优先级与继承</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Cascade_layers">层叠层</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/The_box_model">盒模型</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Backgrounds_and_borders">背景与边框</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Handling_different_text_directions">处理不同方向的文本</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Overflowing_content">溢出的内容</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Values_and_units">CSS 值和单位</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS">在 CSS 中调整大小</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Images_media_form_elements">图像、媒体和表单元素</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Styling_tables">样式化表格</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Advanced_styling_effects">高级区块效果</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Debugging_CSS">调试 CSS</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Organizing">组织 CSS</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Fundamental_CSS_comprehension">基本的 CSS 理解</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/Creating_fancy_letterheaded_paper">创建精美的信纸</a></li><li><a href="/zh-CN/docs/Learn/CSS/Building_blocks/A_cool_looking_box">一个漂亮的盒子</a></li></ol></details></li><li><details><summary>样式化文本</summary><ol><li><a href="/zh-CN/docs/Learn/CSS/Styling_text">为文本添加样式（样式化文本）</a></li><li><a href="/zh-CN/docs/Learn/CSS/Styling_text/Fundamentals">基本文本和字体样式</a></li><li><a href="/zh-CN/docs/Learn/CSS/Styling_text/Styling_lists">为列表添加样式</a></li><li><a href="/zh-CN/docs/Learn/CSS/Styling_text/Styling_links">样式化链接</a></li><li><a href="/zh-CN/docs/Learn/CSS/Styling_text/Web_fonts">Web 字体</a></li><li><a href="/zh-CN/docs/Learn/CSS/Styling_text/Typesetting_a_homepage">作业：排版社区大学首页</a></li></ol></details></li><li><details><summary>CSS 排版</summary><ol><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout">CSS 布局</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Introduction">介绍 CSS 布局</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Normal_Flow">常规流布局</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Flexbox">弹性盒子</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Grids">网格</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Floats">浮动</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Positioning">定位</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Multiple-column_Layout">多列布局</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Responsive_Design">响应式设计</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Media_queries">媒体查询入门指南</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Legacy_Layout_Methods">传统的布局方法</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Supporting_Older_Browsers">支持旧浏览器</a></li><li><a href="/zh-CN/docs/Learn/CSS/CSS_layout/Fundamental_Layout_Comprehension">作业：基本布局理解</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/JavaScript">JavaScript——用户端动态脚本</a></li><li><details><summary>JavaScript 第一步</summary><ol><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps">JavaScript 第一步</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/What_is_JavaScript">什么是 JavaScript？</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/A_first_splash">JavaScript 初体验</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/What_went_wrong">查找并解决 JavaScript 代码的错误</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/Variables">如何存储你需要的信息——变量</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/Math">JavaScript 中的基础数学 — 数字和操作符</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/Strings">文本处理——JavaScript 中的字符串</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/Useful_string_methods">有用的字符串方法</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/Arrays">数组</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/First_steps/Silly_story_generator">笑话生成器</a></li></ol></details></li><li><details><summary>JavaScript 基础</summary><ol><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks">创建 JavaScript 代码块</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks/conditionals">在代码中做决定——条件语句</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks/Looping_code">循环吧，代码</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks/Functions">函数——可复用的代码块</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks/Build_your_own_function">创建你自己的函数</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks/Return_values">函数返回值</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks/Events">事件介绍</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks/Event_bubbling">事件冒泡</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Building_blocks/Image_gallery">图片库</a></li></ol></details></li><li><details><summary>JavaScript 对象介绍</summary><ol><li><a href="/zh-CN/docs/Learn/JavaScript/Objects">JavaScript 对象入门</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Objects/Basics">JavaScript 对象基础</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Objects/Object_prototypes">对象原型</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Objects/Object-oriented_programming">面向对象编程基本概念</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Objects/Classes_in_JavaScript">JavaScript 中的类</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Objects/JSON">使用 JSON</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Objects/Object_building_practice">实践对象构造</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Objects/Adding_bouncing_balls_features">为“弹球”示例添加新功能</a></li></ol></details></li><li><details><summary>异步 JavaScript</summary><ol><li><a href="/zh-CN/docs/Learn/JavaScript/Asynchronous">异步 JavaScript</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Asynchronous/Introducing">异步 JavaScript 简介</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Asynchronous/Promises">如何使用 Promise</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Asynchronous/Implementing_a_promise-based_API">如何实现基于 Promise 的 API</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Asynchronous/Introducing_workers">workers 简介</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Asynchronous/Sequencing_animations">序列动画</a></li></ol></details></li><li><details><summary>客户端 Web API</summary><ol><li><a href="/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs">客户端 Web API</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Introduction">Web API 简介</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Manipulating_documents">操作文档</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Fetching_data">从服务器获取数据</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Third_party_APIs">第三方 API</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Drawing_graphics">绘图</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Video_and_audio_APIs">视频和音频 API</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Client-side_storage">客户端存储</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/Forms">Web 表单——与用户数据打交道</a></li><li><details><summary>Web 表单核心</summary><ol><li><a href="/zh-CN/docs/Learn/Forms">Web 表单构建块</a></li><li><a href="/zh-CN/docs/Learn/Forms/Your_first_form">创建我的第一个表单</a></li><li><a href="/zh-CN/docs/Learn/Forms/How_to_structure_a_web_form">如何构建 HTML 表单</a></li><li><a href="/zh-CN/docs/Learn/Forms/Basic_native_form_controls">原生表单部件</a></li><li><a href="/zh-CN/docs/Learn/Forms/HTML5_input_types">HTML5 的输入（input）类型</a></li><li><a href="/zh-CN/docs/Learn/Forms/Other_form_controls">其他表单控件</a></li><li><a href="/zh-CN/docs/Learn/Forms/Styling_web_forms">样式化 Web 表单</a></li><li><a href="/zh-CN/docs/Learn/Forms/Advanced_form_styling">表单样式化进阶</a></li><li><a href="/zh-CN/docs/Learn/Forms/UI_pseudo-classes">UI 伪类</a></li><li><a href="/zh-CN/docs/Learn/Forms/Form_validation">表单数据校验</a></li><li><a href="/zh-CN/docs/Learn/Forms/Sending_and_retrieving_form_data">发送表单数据</a></li></ol></details></li><li><details><summary>Web 表单进阶</summary><ol><li><a href="/zh-CN/docs/Learn/Forms/How_to_build_custom_form_controls">如何构建自定义表单控件</a></li><li><a href="/zh-CN/docs/Learn/Forms/Sending_forms_through_JavaScript">使用 JavaScript 发送表单</a></li><li><a href="/zh-CN/docs/Learn/Forms/Property_compatibility_table_for_form_controls">表单控件兼容性列表</a></li><li><a href="/zh-CN/docs/Learn/Forms/HTML_forms_in_legacy_browsers">旧式浏览器中的 HTML 表单</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/Accessibility">无障碍——使每个人都能使用 Web</a></li><li><details><summary>无障碍指南</summary><ol><li><a href="/zh-CN/docs/Learn/Accessibility">无障碍</a></li><li><a href="/zh-CN/docs/Learn/Accessibility/What_is_accessibility">什么是无障碍？</a></li><li><a href="/zh-CN/docs/Learn/Accessibility/HTML">HTML：无障碍的良好基础</a></li><li><a href="/zh-CN/docs/Learn/Accessibility/CSS_and_JavaScript">CSS 和 JavaScript 无障碍最佳实践</a></li><li><a href="/zh-CN/docs/Learn/Accessibility/WAI-ARIA_basics">WAI-ARIA 基础</a></li><li><a href="/zh-CN/docs/Learn/Accessibility/Multimedia">多媒体无障碍</a></li><li><a href="/zh-CN/docs/Learn/Accessibility/Mobile">移动端无障碍</a></li><li><a href="/zh-CN/docs/Learn/Accessibility/Accessibility_troubleshooting">测验：无障碍疑难解答</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/Performance">性能——使网站快速响应</a></li><li><details><summary>性能指南</summary><ol><li><a href="/zh-CN/docs/Learn/Performance">Web 性能</a></li><li><a href="/zh-CN/docs/Learn/Performance/why_web_performance">Web 性能的重要性</a></li><li><a href="/zh-CN/docs/Learn/Performance/What_is_web_performance">什么是 web 性能？</a></li><li><a href="/zh-CN/docs/Learn/Performance/Perceived_performance">感知性能</a></li><li><a href="/zh-CN/docs/Learn/Performance/Measuring_performance">测量性能</a></li><li><a href="/zh-CN/docs/Learn/Performance/Multimedia">多媒体：图片</a></li><li><a href="/zh-CN/docs/Learn/Performance/video">多媒体：视频</a></li><li><a href="/zh-CN/docs/Learn/Performance/JavaScript">JavaScript 性能优化</a></li><li><a href="/zh-CN/docs/Learn/Performance/HTML">HTML 性能优化</a></li><li><a href="/zh-CN/docs/Learn/Performance/CSS">CSS 性能优化</a></li><li><a href="/zh-CN/docs/Learn/Performance/business_case_for_performance">web 性能的商业案例</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/MathML">MathML——使用 MathML 语言撰写数学表达式</a></li><li><details open=""><summary>MathML 第一步</summary><ol><li><a href="/zh-CN/docs/Learn/MathML/First_steps">MathML 入门概述</a></li><li><a href="/zh-CN/docs/Learn/MathML/First_steps/Getting_started">MathML 使用入门</a></li><li><a href="/zh-CN/docs/Learn/MathML/First_steps/Text_containers">MathML 文本容器</a></li><li><a href="/zh-CN/docs/Learn/MathML/First_steps/Fractions_and_roots">MathML 分数和根号</a></li><li><em><a href="/zh-CN/docs/Learn/MathML/First_steps/Scripts" aria-current="page">MathML 附加符号</a></em></li><li><a href="/zh-CN/docs/Learn/MathML/First_steps/Tables">MathML 表格</a></li><li><a href="/zh-CN/docs/Learn/MathML/First_steps/Three_famous_mathematical_formulas">三个著名的数学公式</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/../Games">游戏——开发 Web 游戏</a></li><li><details><summary>指南和基础教程</summary><ol><li><a href="/zh-CN/docs/Games/Introduction">Web 游戏开发简介</a></li><li><a href="/zh-CN/docs/Games/Techniques">游戏开发技术</a></li><li><a href="/zh-CN/docs/Games/Tutorials">教程</a></li><li><a href="/zh-CN/docs/Games/Publishing_games">发布游戏</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/Tools_and_testing">工具与测试</a></li><li><details><summary>客户端 web 开发工具</summary><ol><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools">理解客户端 web 开发工具</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Overview">客户端工具概述</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Command_line">命令行速成课</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Package_management">软件包管理基础</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Introducing_complete_toolchain">介绍完整的工具链</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Deployment">部署我们的应用</a></li></ol></details></li><li><details><summary>客户端框架介绍</summary><ol><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Introduction">客户端框架介绍</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Main_features">框架的主要特性</a></li></ol></details></li><li><details><summary>React</summary><ol><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_getting_started">React 入门</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_todo_list_beginning">开始我们的 React 待办清单</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_components">组件化我们的 React App</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_interactivity_events_state">React interactivity: Events and state</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_interactivity_filtering_conditional_rendering">React interactivity: Editing, filtering, conditional rendering</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_accessibility">Accessibility in React</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_resources">React resources</a></li></ol></details></li><li><details><summary>Ember</summary><ol><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_getting_started">Getting started with Ember</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_structure_componentization">Ember app structure and componentization</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_interactivity_events_state">Ember interactivity: Events, classes and state</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_conditional_footer">Ember Interactivity: Footer functionality, conditional rendering</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_routing">Routing in Ember</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_resources">Ember resources and troubleshooting</a></li></ol></details></li><li><details><summary>Vue</summary><ol><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_getting_started">开始使用 Vue</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_first_component">创建第一个 Vue 组件</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_rendering_lists">渲染 Vue 组件列表</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_methods_events_models">使用 Vue event、method 和 model 添加一个新的 todo 表单</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_styling">使用 CSS 为 Vue 组件添加样式</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_computed_properties">Vue 中的计算属性</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_conditional_rendering">Vue 中的条件渲染：编辑现有的待办事项</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_refs_focus_management">使用 Vue 模板引用进行焦点管理</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_resources">Vue 资源</a></li></ol></details></li><li><details><summary>Svelte</summary><ol><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_getting_started">Svelte 入门</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_Todo_list_beginning">开始编写我们的 Svelte 待办事项列表应用程序</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_variables_props">Svelte 中的动态行为：变量和属性</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_components">将我们的 Svelte 应用组件化</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_reactivity_lifecycle_accessibility">Svelte 进阶：响应式、生命周期以及无障碍</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_stores">使用 Svelte store</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_TypeScript">Svelte 对 TypeScript 的支持</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_deployment_next">部署以及下一步</a></li></ol></details></li><li><details><summary>Angular</summary><ol><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_getting_started">Angular 入门</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_todo_list_beginning">Beginning our Angular todo list app</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_styling">Styling our Angular app</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_item_component">Creating an item component</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_filtering">Filtering our to-do items</a></li><li><a class="only-in-en-us" title="此页面目前仅提供英文版本" href="/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_building">Building Angular applications and further resources</a></li></ol></details></li><li><details><summary>Git 和 GitHub</summary><ol><li><a href="/zh-CN/docs/Learn/Tools_and_testing/GitHub">Git 和 GitHub</a></li></ol></details></li><li><details><summary>跨浏览器测试</summary><ol><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing">跨浏览器测试</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Introduction">跨浏览器测试介绍</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Testing_strategies">测试的策略</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/HTML_and_CSS">处理常见的 HTML 和 CSS 问题</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/JavaScript">处理常见的 JavaScript 问题</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Accessibility">解决常见的无障碍问题</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Feature_detection">实现特性检测</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Automated_testing">自动化测试简介</a></li><li><a href="/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Your_own_automation_environment">搭建自己的自动化测试环境</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/Server-side">服务端网页编程</a></li><li><details><summary>第一步</summary><ol><li><a href="/zh-CN/docs/Learn/Server-side/First_steps">服务端网站编程的第一步</a></li><li><a href="/zh-CN/docs/Learn/Server-side/First_steps/Introduction">服务端编程介绍</a></li><li><a href="/zh-CN/docs/Learn/Server-side/First_steps/Client-Server_overview">客户端服务端交互概述</a></li><li><a href="/zh-CN/docs/Learn/Server-side/First_steps/Web_frameworks">服务端 web 框架</a></li><li><a href="/zh-CN/docs/Learn/Server-side/First_steps/Website_security">站点安全</a></li></ol></details></li><li><details><summary>Django Web 框架（Python）</summary><ol><li><a href="/zh-CN/docs/Learn/Server-side/Django">Django Web 框架 (python)</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Introduction">Django 介绍</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/development_environment">设置 Django 开发环境</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Tutorial_local_library_website">Django Tutorial: The Local Library website</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/skeleton_website">Django Tutorial Part 2: 创建网站的地基</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Models">Django Tutorial Part 3: 使用模型</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Admin_site">Django Tutorial Part 4: Django 管理员站点</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Home_page">Django 教程 5：主页构建</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Generic_views">Django 教程 6: 通用列表和详细信息视图</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Sessions">Django 教程 7: 会话框架</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Authentication">Django 教程 8：用户授权与许可</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Forms">Django 教程 9: 使用表单</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Testing">Django 教程 10: 测试 Django 网页应用</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/Deployment">Django 教程 11：部署 Django 到生产环境</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/web_application_security">Django Web 应用安全</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Django/django_assessment_blog">评估：DIY Django 微博客</a></li></ol></details></li><li><details><summary>Express Web 框架（Node.js/JavaScript）</summary><ol><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs">Express Web 框架（Node.js/JavaScript）</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/Introduction">Express/Node 入门</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/development_environment">设置 Node 开发环境</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/Tutorial_local_library_website">Express 教程：本地图书馆网站</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/skeleton_website">Express 教程 2：创建站点框架</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/mongoose">Express 教程 3：使用数据库 (Mongoose)</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/routes">Express 教程 4：路由和控制器</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/Displaying_data">Express 教程 5: 呈现图书馆数据</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/forms">Express 教程 6: 使用表单</a></li><li><a href="/zh-CN/docs/Learn/Server-side/Express_Nodejs/deployment">Express 教程 7: 部署到生产环境</a></li></ol></details></li><li class="section"><a href="/zh-CN/docs/Learn/Common_questions">更多资源</a></li><li><details><summary>常见问题</summary><ol><li><a href="/zh-CN/docs/Learn/Common_questions">常见问题</a></li><li><a href="/zh-CN/docs/Learn/HTML/Howto">使用 HTML 解决常见问题</a></li><li><a href="/zh-CN/docs/Learn/CSS/Howto">解决常见的 CSS 问题</a></li><li><a href="/zh-CN/docs/Learn/JavaScript/Howto">解决 JavaSctript 代码的常见问题</a></li><li><a href="/zh-CN/docs/Learn/Common_questions/Web_mechanics">Web 机制</a></li><li><a href="/zh-CN/docs/Learn/Common_questions/Tools_and_setup">工具和安装</a></li><li><a href="/zh-CN/docs/Learn/Common_questions/Design_and_accessibility">设计与无障碍</a></li></ol></details></li></ol></div></div><section class="place side"></section></nav></aside><div class="toc-container"><aside class="toc"><nav><div class="document-toc-container"><section class="document-toc"><header><h2 class="document-toc-heading">在本文中</h2></header><ul class="document-toc-list"><li class="document-toc-item "><a class="document-toc-link" href="#下标和上标">下标和上标</a></li><li class="document-toc-item "><a class="document-toc-link" href="#正下标和正上标">正下标和正上标</a></li><li class="document-toc-item "><a class="document-toc-link" href="#其他运算符属性">其他运算符属性</a></li><li class="document-toc-item "><a class="document-toc-link" href="#总结">总结</a></li><li class="document-toc-item "><a class="document-toc-link" href="#参见">参见</a></li></ul></section></div></nav></aside><section class="place side"></section></div></div><main id="content" class="main-content "><article class="main-page-content" lang="zh-CN"><header><h1>MathML 附加符号</h1></header><div class="section-content"><ul class="prev-next"> <li><a class="button secondary" href="/zh-CN/docs/Learn/MathML/First_steps/Fractions_and_roots"><span class="button-wrap"> 上一页 </span></a></li> <li><a class="button secondary" href="/zh-CN/docs/Learn/MathML/First_steps"><span class="button-wrap"> 概述：MathML 入门概述</span></a></li> <li><a class="button secondary" href="/zh-CN/docs/Learn/MathML/First_steps/Tables"><span class="button-wrap"> 下一页 </span></a></li> </ul> <p>我们继续回顾基本数学符号，并重点介绍如何使用附加符号构建 MathML 元素。</p> <figure class="table-container"><table> <tbody> <tr> <th scope="row">前提：</th> <td> 基本的计算机操作能力、<a href="/zh-CN/docs/Learn/Getting_started_with_the_web/Installing_basic_software">安装基本软件</a>、<a href="/zh-CN/docs/Learn/Getting_started_with_the_web/Dealing_with_files">处理文件</a>的基本知识，以及 HTML 基础知识（可以学习 <a href="/zh-CN/docs/Learn/HTML/Introduction_to_HTML">HTML 入门</a>。） </td> </tr> <tr> <th scope="row">目标：</th> <td>熟悉基本的 MathML 上下标元素。</td> </tr> </tbody> </table></figure></div><section aria-labelledby="下标和上标"><h2 id="下标和上标"><a href="#下标和上标">下标和上标</a></h2><div class="section-content"><p>类似于我们在<a href="/zh-CN/docs/Learn/MathML/First_steps/Fractions_and_roots">上一篇文章</a>中所学习的，<code><msub></code>、<code><msup></code> 和 <code><msubsup></code> 具有特殊的结构，它们恰好有两个元素（<code><msub></code>、<code><msup></code>）或三个元素（<code><msubsup></code>）：</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html notranslate"><code><p> msub: <math> <msub> <mtext>child1</mtext> <mtext>child2</mtext> </msub> </math> </p> <p> msup: <math> <msup> <mtext>child1</mtext> <mtext>child2</mtext> </msup> </math> </p> <p> msubsup: <math> <msubsup> <mtext>child1</mtext> <mtext>child2</mtext> <mtext>child3</mtext> </msubsup> </math> </p> </code></pre></div> <p>以下是在你的浏览器中的上述示例的渲染结果。</p><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="下标和上标 sample" id="frame_下标和上标" width="700" height="200" src="about:blank" data-live-path="/zh-CN/docs/Learn/MathML/First_steps/Scripts" data-live-id="下标和上标" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>可以看出：</p> <ul> <li><code><msub></code> 元素的第二个子元素作为其第一个子元素的下标附加。</li> <li><code><msup></code> 元素的第二个子元素作为其第一个子元素的上标附加。</li> <li><code><msubsup></code> 元素的第二个和第三个子元素分别作为其第一个子元素的下标和上标附加。</li> <li>上下标内的文本会缩小显示。</li> </ul> <div class="notecard note"> <p><strong>备注：</strong>MathML 元素 <code><msub></code> 和 <code><msup></code> 与 HTML 元素 <a href="/zh-CN/docs/Web/HTML/Element/sub"><code><sub></code></a> 和 <a href="/zh-CN/docs/Web/HTML/Element/sup"><code><sup></code></a> 不同。它们允许开发者将任意的 MathML 子树作为附加符号，而不仅仅是文本。</p> </div></div></section><section aria-labelledby="正下标和正上标"><h2 id="正下标和正上标"><a href="#正下标和正上标">正下标和正上标</a></h2><div class="section-content"><p><code><munder></code>、<code><mover></code> 和 <code><munderover></code> 元素与之前介绍的元素非常相似，只是它们用于附加正下标（underscript）和正上标（overscirpt）。我们不会提供详细信息，而是让你自己通过以下练习来了解它们的定义。</p></div></section><section aria-labelledby="主动学习：识别正下标和正上标"><h3 id="主动学习：识别正下标和正上标"><a href="#主动学习：识别正下标和正上标">主动学习：识别正下标和正上标</a></h3><div class="section-content"><p>在下面的示例中，试着猜测神秘元素的名称（用问号表示），然后点击按钮来显示答案：</p> <div class="code-example"><pre class="brush: html hidden notranslate"><code><p> <code>&lt;<span>????????</span>&gt;</code> 元素正好具有两个子元素（child1、child2）： <math> <mover> <mtext>child1</mtext> <mtext>child2</mtext> </mover> </math> </p> <p> <code>&lt;<span>????????</span>&gt;</code> 元素正好具有三个子元素（child1、child2 以及 child3）： <math> <munderover> <mtext>child1</mtext> <mtext>child2</mtext> <mtext>child3</mtext> </munderover> </math> </p> <p> <code>&lt;<span>????????</span>&gt;</code> 元素正好具有两个子元素（child1、child2）： <math> <munder> <mtext>child1</mtext> <mtext>child2</mtext> </munder> </math> </p> <p><input type="button" id="showSolution" value="展示结果" /></p> </code></pre></div> <div class="code-example"><pre class="brush: css hidden notranslate"><code>p { padding: 0.5em; } </code></pre></div> <div class="code-example"><pre class="brush: js hidden notranslate"><code>document.getElementById("showSolution").addEventListener("click", () => { const maths = Array.from(document.getElementsByTagName("math")); Array.from(document.getElementsByTagName("span")).forEach((span, index) => { span.textContent = maths[index].firstElementChild.tagName; }); }); </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="主动学习：识别正下标和正上标 sample" id="frame_主动学习：识别正下标和正上标" width="700" height="400" src="about:blank" data-live-path="/zh-CN/docs/Learn/MathML/First_steps/Scripts" data-live-id="主动学习：识别正下标和正上标" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div></div></section><section aria-labelledby="主动学习：识别附加符号元素"><h3 id="主动学习：识别附加符号元素"><a href="#主动学习：识别附加符号元素">主动学习：识别附加符号元素</a></h3><div class="section-content"><p>以下的 MathML 公式包含了更复杂的表达式，嵌套了分数、根号和附加符号元素。尝试猜测使用了 <code><msub></code>、<code><msup></code>、<code><msubsup></code>、<code><munder></code>、<code><mover></code>、<code><munderover></code> 的元素。每次当你点击这样的元素时，它会被突出显示，并显示确认信息。最后，阅读 MathML 源代码以验证是否与你的预期相符。</p> <div class="code-example"><pre class="brush: html hidden notranslate"><code><!doctype html> <html lang="en-US"> <head> <meta charset="utf-8" /> <title>带有附加符号元素的页面</title> <link rel="stylesheet" href="https://fred-wang.github.io/MathFonts/LatinModern/mathfonts.css" /> </head> <body> <math display="block"> <mroot> <mrow> <munder> <mi>β</mi> <mo>⎵</mo> </munder> </mrow> <mn>3</mn> </mroot> <mo>+</mo> <mfrac> <mrow ><mo>|</mo> <mover> <mi>α</mi> <mo>→</mo> </mover> <mo>|</mo> </mrow> <msup> <mi>s</mi> <mn>3</mn> </msup> </mfrac> <mo>−</mo> <mrow> <munderover> <mo>∑</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msqrt> <mrow> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo>−</mo> <msubsup> <mi>K</mi> <mn>0</mn> <mi>i</mi> </msubsup> </mrow> </msqrt> </mrow> </math> <input type="button" id="clearOutput" value="重置" /> <div id="output"></div> </body> </html> </code></pre></div> <div class="code-example"><pre class="brush: css hidden notranslate"><code>.highlight { color: red; } math { font-size: 200%; } </code></pre></div> <div class="code-example"><pre class="brush: js hidden notranslate"><code>const scriptedElements = Array.from( document.querySelectorAll("msub, msup, msubsup, munder, mover, munderover"), ); const outputDiv = document.getElementById("output"); function clearHighlight() { scriptedElements.forEach((scripted) => { scripted.classList.remove("highlight"); }); } scriptedElements.forEach((scripted) => { scripted.addEventListener("click", () => { clearHighlight(); scripted.classList.add("highlight"); outputDiv.insertAdjacentHTML( "beforeend", `<p><strong>你点击了 <code>&lt;${scripted.tagName}&gt;</code> 元素。</strong></p>`, ); }); }); document.getElementById("clearOutput").addEventListener("click", () => { clearHighlight(); outputDiv.innerHTML = ""; }); </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="主动学习：识别附加符号元素 sample" id="frame_主动学习：识别附加符号元素" width="700" height="400" src="about:blank" data-live-path="/zh-CN/docs/Learn/MathML/First_steps/Scripts" data-live-id="主动学习：识别附加符号元素" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div></div></section><section aria-labelledby="其他运算符属性"><h2 id="其他运算符属性"><a href="#其他运算符属性">其他运算符属性</a></h2><div class="section-content"><p>我们之前已经了解了 <code><mo></code> 元素的一些<a href="/zh-CN/docs/Learn/MathML/First_steps/Text_containers#mo_%E7%9A%84%E8%BF%90%E7%AE%97%E7%AC%A6%E5%B1%9E%E6%80%A7">属性</a>，包括在垂直方向上的拉伸和间距。现在有了附加符号元素，我们可以扩展该列表。我们将通过修改我们的<a href="#%E4%B8%BB%E5%8A%A8%E5%AD%A6%E4%B9%A0%EF%BC%9A%E8%AF%86%E5%88%AB%E9%99%84%E5%8A%A0%E7%AC%A6%E5%8F%B7%E5%85%83%E7%B4%A0">上一个示例</a>来实现这一点。</p></div></section><section aria-labelledby="在水平方向上的拉伸"><h3 id="在水平方向上的拉伸"><a href="#在水平方向上的拉伸">在水平方向上的拉伸</a></h3><div class="section-content"><p>首先，让我们进行以下替换： <math> <mi>β</mi> <mo>≔</mo> <mrow> <msub> <mi>z</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>z</mi> <mn>2</mn> </msub> </mrow> </math> 和 <math> <mi>α</mi> <mo>≔</mo> <mrow> <msub> <mi>v</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>v</mi> <mn>2</mn> </msub> </mrow> </math>： </p> <div class="code-example"><pre class="brush: html hidden notranslate"><code><!doctype html> <html lang="zh-CN"> <head> <meta charset="utf-8" /> <title>带有水平拉伸操作符的页面</title> <link rel="stylesheet" href="https://fred-wang.github.io/MathFonts/LatinModern/mathfonts.css" /> </head> <body> <math display="block"> <mroot> <mrow> <munder> <mrow> <msub> <mi>z</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>z</mi> <mn>2</mn> </msub> </mrow> <mo>⎵</mo> </munder> </mrow> <mn>3</mn> </mroot> <mo>+</mo> <mfrac> <mrow ><mo>|</mo> <mover> <mrow> <msub> <mi>v</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>v</mi> <mn>2</mn> </msub> </mrow> <mo>→</mo> </mover> <mo>|</mo> </mrow> <msup> <mi>s</mi> <mn>3</mn> </msup> </mfrac> <mo>−</mo> <mrow> <munderover> <mo>∑</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msqrt> <mrow> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo>−</mo> <msubsup> <mi>K</mi> <mn>0</mn> <mi>i</mi> </msubsup> </mrow> </msqrt> </mrow> </math> </body> </html> </code></pre></div> <div class="code-example"><pre class="brush: css hidden notranslate"><code>.highlight { color: red; } math { font-size: 200%; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="在水平方向上的拉伸 sample" id="frame_在水平方向上的拉伸" width="700" height="200" src="about:blank" data-live-path="/zh-CN/docs/Learn/MathML/First_steps/Scripts" data-live-id="在水平方向上的拉伸" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>可以看出底部括号“⎵”和右箭头“→”在水平方向上会延伸以覆盖被替代值的宽度。回想一下，<a href="/zh-CN/docs/Learn/MathML/First_steps/Text_containers#active_learning_stretchy_operators">一些竖直运算符可以伸展</a>，以覆盖 <code><mrow></code> 中非伸展兄弟节点的高度。类似地，一些水平运算符可以伸展以覆盖 <code><munder></code>、<code><mover></code> 或 <code><munderover></code> 元素中非伸展兄弟节点的宽度。</p> <div class="notecard note"> <p><strong>备注：</strong>伸展适用于 <code><munder></code>、<code><mover></code> 或 <code><munderover></code> 元素的任何子元素，不仅仅是正下标或正上标。</p> </div></div></section><section aria-labelledby="大型运算符和极限"><h3 id="大型运算符和极限"><a href="#大型运算符和极限">大型运算符和极限</a></h3><div class="section-content"><p>到目前为止，我们的示例实际上是使用 <a href="/zh-CN/docs/Learn/MathML/First_steps/Getting_started#display_%E5%B1%9E%E6%80%A7"><code>display="block"</code></a> 属性呈现的。让我们看一下同一个示例，在没有该属性的情况下渲染的效果：</p> <div class="code-example"><pre class="brush: html hidden notranslate"><code><!doctype html> <html lang="zh-CN"> <head> <meta charset="utf-8" /> <title>极限符号被挪动并且大型运算符变小的页面</title> <link rel="stylesheet" href="https://fred-wang.github.io/MathFonts/LatinModern/mathfonts.css" /> </head> <body> <math> <mroot> <mrow> <munder> <mrow> <msub> <mi>z</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>z</mi> <mn>2</mn> </msub> </mrow> <mo>⎵</mo> </munder> </mrow> <mn>3</mn> </mroot> <mo>+</mo> <mfrac> <mrow ><mo>|</mo> <mover> <mrow> <msub> <mi>v</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>v</mi> <mn>2</mn> </msub> </mrow> <mo>→</mo> </mover> <mo>|</mo> </mrow> <msup> <mi>s</mi> <mn>3</mn> </msup> </mfrac> <mo>−</mo> <mrow> <munderover> <mo>∑</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msqrt> <mrow> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo>−</mo> <msubsup> <mi>K</mi> <mn>0</mn> <mi>i</mi> </msubsup> </mrow> </msqrt> </mrow> </math> </body> </html> </code></pre></div> <div class="code-example"><pre class="brush: css hidden notranslate"><code>.highlight { color: red; } math { font-size: 200%; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="大型运算符和极限 sample" id="frame_大型运算符和极限" width="700" height="200" src="about:blank" data-live-path="/zh-CN/docs/Learn/MathML/First_steps/Scripts" data-live-id="大型运算符和极限" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>不出所料，公式不再居中，渲染方式发生变动，导致高度最小化。注意求和符号，可以看到求和符号变小了，并且 <code><munderover></code> 元素的附加符号现在以下标和上标的方式附加在其上！这是由于“∑”运算符的两个属性：</p> <ul> <li><em>largeop</em>：如果 <code><math></code> 标签具有 <code>display="block"</code> 属性，则使用更大的字形绘制运算符。</li> <li><em>movablelimits</em>：如果 <code><math></code> 标签没有 <code>display="block"</code> 属性，则将附加在运算符上的正下标和正上标分别渲染为下标和上标。</li> </ul> <div class="notecard note"> <p><strong>备注：</strong> <em>largeop</em> 属性实际上与附加符号无关，尽管具有此属性的运算符通常会有附加符号。<em>movablelimits</em> 属性也适用于 <code><munder></code> 和 <code><mover></code> 元素。</p> </div></div></section><section aria-labelledby="总结"><h2 id="总结"><a href="#总结">总结</a></h2><div class="section-content"><p>在本文中，我们完成了对引入下标、上标、正下标和正上标的基本布局元素 <code><msub></code>、<code><msup></code>、<code><msubsup></code>、<code><munder></code>、<code><mover></code> 以及 <code><munderover></code> 的介绍。在介绍这些元素的过程中，我们顺便介绍了 <code><mo></code> 元素的新属性。在下一篇文章中，我们将继续关注<a href="/zh-CN/docs/Learn/MathML/First_steps/Tables">表格布局</a>。</p><ul class="prev-next"> <li><a class="button secondary" href="/zh-CN/docs/Learn/MathML/First_steps/Fractions_and_roots"><span class="button-wrap"> 上一页 </span></a></li> <li><a class="button secondary" href="/zh-CN/docs/Learn/MathML/First_steps"><span class="button-wrap"> 概述：MathML 入门概述</span></a></li> <li><a class="button secondary" href="/zh-CN/docs/Learn/MathML/First_steps/Tables"><span class="button-wrap"> 下一页 </span></a></li> </ul></div></section><section aria-labelledby="参见"><h2 id="参见"><a href="#参见">参见</a></h2><div class="section-content"><ul> <li><a href="/zh-CN/docs/Web/MathML/Element/msub"><msub>元素</msub></a></li> <li><a href="/zh-CN/docs/Web/MathML/Element/msup"><msup>元素</msup></a></li> <li><a href="/zh-CN/docs/Web/MathML/Element/msubsup"><msubsup>元素</msubsup></a></li> <li><a href="/zh-CN/docs/Web/MathML/Element/munder"><munder>元素</munder></a></li> <li><a href="/zh-CN/docs/Web/MathML/Element/mover"><mover>元素</mover></a></li> <li><a href="/zh-CN/docs/Web/MathML/Element/munderover"><munderover>元素</munderover></a></li> </ul></div></section></article><aside class="article-footer"><div class="article-footer-inner"><div class="svg-container"><svg xmlns="http://www.w3.org/2000/svg" width="162" height="162" viewBox="0 0 162 162" fill="none" role="none"><mask id="b" fill="#fff"><path d="M97.203 47.04c8.113-7.886 18.004-13.871 28.906-17.492a78 78 0 0 1 33.969-3.39c11.443 1.39 22.401 5.295 32.024 11.411s17.656 14.28 23.476 23.86c5.819 9.579 9.269 20.318 10.083 31.385a69.85 69.85 0 0 1-5.387 32.44c-4.358 10.272-11.115 19.443-19.747 26.801-8.632 7.359-18.908 12.709-30.034 15.637l-6.17-21.698c7.666-2.017 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元信息</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Introduction_to_HTML/HTML_text_fundamentals\">HTML 文本处理基础</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Creating_hyperlinks\">创建超链接</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Advanced_text_formatting\">文本格式进阶</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Document_and_website_structure\">文档与网站架构</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Debugging_HTML\">HTML 调试</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Marking_up_a_letter\">标记信件</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Introduction_to_HTML/Structuring_a_page_of_content\">构建网页内容</a></li></ol></details></li><li><details><summary>多媒体与嵌入</summary><ol><li><a href=\"/zh-CN/docs/Learn/HTML/Multimedia_and_embedding\">多媒体与嵌入</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Images_in_HTML\">HTML 中的图片</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Video_and_audio_content\">视频和音频内容</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Other_embedding_technologies\">从 object 到 iframe——其他嵌入技术</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Adding_vector_graphics_to_the_Web\">向 web 中添加矢量图形</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images\">响应式图片</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Multimedia_and_embedding/Mozilla_splash_page\">Mozilla 欢迎页面</a></li></ol></details></li><li><details><summary>HTML 表格</summary><ol><li><a href=\"/zh-CN/docs/Learn/HTML/Tables\">HTML 表格</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Tables/Basics\">HTML 表格基础</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Tables/Advanced\">HTML 表格进阶特性和无障碍</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Tables/Structuring_planet_data\">作业：构建行星数据</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/CSS\">CSS——设计 Web</a></li><li><details><summary>CSS 第一步</summary><ol><li><a href=\"/zh-CN/docs/Learn/CSS/First_steps\">CSS 入门概述</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/First_steps/What_is_CSS\">什么是 CSS?</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/First_steps/Getting_started\">让我们开始 CSS 的学习之旅</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/First_steps/How_CSS_is_structured\">CSS 的组成</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/First_steps/How_CSS_works\">CSS 如何运行</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/First_steps/Styling_a_biography_page\">运用你的新知识</a></li></ol></details></li><li><details><summary>CSS 基础</summary><ol><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks\">CSS 构建</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Selectors\">CSS 选择器</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Selectors/Type_Class_and_ID_Selectors\">类型、类和 ID 选择器</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Selectors/Attribute_selectors\">属性选择器</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Selectors/Pseudo-classes_and_pseudo-elements\">伪类和伪元素</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Selectors/Combinators\">关系选择器</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Cascade_and_inheritance\">层叠、优先级与继承</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Cascade_layers\">层叠层</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/The_box_model\">盒模型</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Backgrounds_and_borders\">背景与边框</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Handling_different_text_directions\">处理不同方向的文本</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Overflowing_content\">溢出的内容</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Values_and_units\">CSS 值和单位</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Sizing_items_in_CSS\">在 CSS 中调整大小</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Images_media_form_elements\">图像、媒体和表单元素</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Styling_tables\">样式化表格</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Advanced_styling_effects\">高级区块效果</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Debugging_CSS\">调试 CSS</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Organizing\">组织 CSS</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Fundamental_CSS_comprehension\">基本的 CSS 理解</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/Creating_fancy_letterheaded_paper\">创建精美的信纸</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Building_blocks/A_cool_looking_box\">一个漂亮的盒子</a></li></ol></details></li><li><details><summary>样式化文本</summary><ol><li><a href=\"/zh-CN/docs/Learn/CSS/Styling_text\">为文本添加样式（样式化文本）</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Styling_text/Fundamentals\">基本文本和字体样式</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Styling_text/Styling_lists\">为列表添加样式</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Styling_text/Styling_links\">样式化链接</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Styling_text/Web_fonts\">Web 字体</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Styling_text/Typesetting_a_homepage\">作业：排版社区大学首页</a></li></ol></details></li><li><details><summary>CSS 排版</summary><ol><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout\">CSS 布局</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Introduction\">介绍 CSS 布局</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Normal_Flow\">常规流布局</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Flexbox\">弹性盒子</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Grids\">网格</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Floats\">浮动</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Positioning\">定位</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Multiple-column_Layout\">多列布局</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Responsive_Design\">响应式设计</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Media_queries\">媒体查询入门指南</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Legacy_Layout_Methods\">传统的布局方法</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Supporting_Older_Browsers\">支持旧浏览器</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/CSS_layout/Fundamental_Layout_Comprehension\">作业：基本布局理解</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/JavaScript\">JavaScript——用户端动态脚本</a></li><li><details><summary>JavaScript 第一步</summary><ol><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps\">JavaScript 第一步</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/What_is_JavaScript\">什么是 JavaScript？</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/A_first_splash\">JavaScript 初体验</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/What_went_wrong\">查找并解决 JavaScript 代码的错误</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/Variables\">如何存储你需要的信息——变量</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/Math\">JavaScript 中的基础数学 — 数字和操作符</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/Strings\">文本处理——JavaScript 中的字符串</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/Useful_string_methods\">有用的字符串方法</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/Arrays\">数组</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/First_steps/Silly_story_generator\">笑话生成器</a></li></ol></details></li><li><details><summary>JavaScript 基础</summary><ol><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks\">创建 JavaScript 代码块</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks/conditionals\">在代码中做决定——条件语句</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks/Looping_code\">循环吧，代码</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks/Functions\">函数——可复用的代码块</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks/Build_your_own_function\">创建你自己的函数</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks/Return_values\">函数返回值</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks/Events\">事件介绍</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks/Event_bubbling\">事件冒泡</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Building_blocks/Image_gallery\">图片库</a></li></ol></details></li><li><details><summary>JavaScript 对象介绍</summary><ol><li><a href=\"/zh-CN/docs/Learn/JavaScript/Objects\">JavaScript 对象入门</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Objects/Basics\">JavaScript 对象基础</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Objects/Object_prototypes\">对象原型</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Objects/Object-oriented_programming\">面向对象编程基本概念</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Objects/Classes_in_JavaScript\">JavaScript 中的类</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Objects/JSON\">使用 JSON</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Objects/Object_building_practice\">实践对象构造</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Objects/Adding_bouncing_balls_features\">为“弹球”示例添加新功能</a></li></ol></details></li><li><details><summary>异步 JavaScript</summary><ol><li><a href=\"/zh-CN/docs/Learn/JavaScript/Asynchronous\">异步 JavaScript</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Asynchronous/Introducing\">异步 JavaScript 简介</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Asynchronous/Promises\">如何使用 Promise</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Asynchronous/Implementing_a_promise-based_API\">如何实现基于 Promise 的 API</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Asynchronous/Introducing_workers\">workers 简介</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Asynchronous/Sequencing_animations\">序列动画</a></li></ol></details></li><li><details><summary>客户端 Web API</summary><ol><li><a href=\"/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs\">客户端 Web API</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Introduction\">Web API 简介</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Manipulating_documents\">操作文档</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Fetching_data\">从服务器获取数据</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Third_party_APIs\">第三方 API</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Drawing_graphics\">绘图</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Video_and_audio_APIs\">视频和音频 API</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Client-side_web_APIs/Client-side_storage\">客户端存储</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/Forms\">Web 表单——与用户数据打交道</a></li><li><details><summary>Web 表单核心</summary><ol><li><a href=\"/zh-CN/docs/Learn/Forms\">Web 表单构建块</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Your_first_form\">创建我的第一个表单</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/How_to_structure_a_web_form\">如何构建 HTML 表单</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Basic_native_form_controls\">原生表单部件</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/HTML5_input_types\">HTML5 的输入（input）类型</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Other_form_controls\">其他表单控件</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Styling_web_forms\">样式化 Web 表单</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Advanced_form_styling\">表单样式化进阶</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/UI_pseudo-classes\">UI 伪类</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Form_validation\">表单数据校验</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Sending_and_retrieving_form_data\">发送表单数据</a></li></ol></details></li><li><details><summary>Web 表单进阶</summary><ol><li><a href=\"/zh-CN/docs/Learn/Forms/How_to_build_custom_form_controls\">如何构建自定义表单控件</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Sending_forms_through_JavaScript\">使用 JavaScript 发送表单</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/Property_compatibility_table_for_form_controls\">表单控件兼容性列表</a></li><li><a href=\"/zh-CN/docs/Learn/Forms/HTML_forms_in_legacy_browsers\">旧式浏览器中的 HTML 表单</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/Accessibility\">无障碍——使每个人都能使用 Web</a></li><li><details><summary>无障碍指南</summary><ol><li><a href=\"/zh-CN/docs/Learn/Accessibility\">无障碍</a></li><li><a href=\"/zh-CN/docs/Learn/Accessibility/What_is_accessibility\">什么是无障碍？</a></li><li><a href=\"/zh-CN/docs/Learn/Accessibility/HTML\">HTML：无障碍的良好基础</a></li><li><a href=\"/zh-CN/docs/Learn/Accessibility/CSS_and_JavaScript\">CSS 和 JavaScript 无障碍最佳实践</a></li><li><a href=\"/zh-CN/docs/Learn/Accessibility/WAI-ARIA_basics\">WAI-ARIA 基础</a></li><li><a href=\"/zh-CN/docs/Learn/Accessibility/Multimedia\">多媒体无障碍</a></li><li><a href=\"/zh-CN/docs/Learn/Accessibility/Mobile\">移动端无障碍</a></li><li><a href=\"/zh-CN/docs/Learn/Accessibility/Accessibility_troubleshooting\">测验：无障碍疑难解答</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/Performance\">性能——使网站快速响应</a></li><li><details><summary>性能指南</summary><ol><li><a href=\"/zh-CN/docs/Learn/Performance\">Web 性能</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/why_web_performance\">Web 性能的重要性</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/What_is_web_performance\">什么是 web 性能？</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/Perceived_performance\">感知性能</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/Measuring_performance\">测量性能</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/Multimedia\">多媒体：图片</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/video\">多媒体：视频</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/JavaScript\">JavaScript 性能优化</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/HTML\">HTML 性能优化</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/CSS\">CSS 性能优化</a></li><li><a href=\"/zh-CN/docs/Learn/Performance/business_case_for_performance\">web 性能的商业案例</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/MathML\">MathML——使用 MathML 语言撰写数学表达式</a></li><li><details open=\"\"><summary>MathML 第一步</summary><ol><li><a href=\"/zh-CN/docs/Learn/MathML/First_steps\">MathML 入门概述</a></li><li><a href=\"/zh-CN/docs/Learn/MathML/First_steps/Getting_started\">MathML 使用入门</a></li><li><a href=\"/zh-CN/docs/Learn/MathML/First_steps/Text_containers\">MathML 文本容器</a></li><li><a href=\"/zh-CN/docs/Learn/MathML/First_steps/Fractions_and_roots\">MathML 分数和根号</a></li><li><em><a href=\"/zh-CN/docs/Learn/MathML/First_steps/Scripts\" aria-current=\"page\">MathML 附加符号</a></em></li><li><a href=\"/zh-CN/docs/Learn/MathML/First_steps/Tables\">MathML 表格</a></li><li><a href=\"/zh-CN/docs/Learn/MathML/First_steps/Three_famous_mathematical_formulas\">三个著名的数学公式</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/../Games\">游戏——开发 Web 游戏</a></li><li><details><summary>指南和基础教程</summary><ol><li><a href=\"/zh-CN/docs/Games/Introduction\">Web 游戏开发简介</a></li><li><a href=\"/zh-CN/docs/Games/Techniques\">游戏开发技术</a></li><li><a href=\"/zh-CN/docs/Games/Tutorials\">教程</a></li><li><a href=\"/zh-CN/docs/Games/Publishing_games\">发布游戏</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/Tools_and_testing\">工具与测试</a></li><li><details><summary>客户端 web 开发工具</summary><ol><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools\">理解客户端 web 开发工具</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Overview\">客户端工具概述</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Command_line\">命令行速成课</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Package_management\">软件包管理基础</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Introducing_complete_toolchain\">介绍完整的工具链</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Deployment\">部署我们的应用</a></li></ol></details></li><li><details><summary>客户端框架介绍</summary><ol><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Introduction\">客户端框架介绍</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Main_features\">框架的主要特性</a></li></ol></details></li><li><details><summary>React</summary><ol><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_getting_started\">React 入门</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_todo_list_beginning\">开始我们的 React 待办清单</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_components\">组件化我们的 React App</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_interactivity_events_state\">React interactivity: Events and state</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_interactivity_filtering_conditional_rendering\">React interactivity: Editing, filtering, conditional rendering</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_accessibility\">Accessibility in React</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/React_resources\">React resources</a></li></ol></details></li><li><details><summary>Ember</summary><ol><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_getting_started\">Getting started with Ember</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_structure_componentization\">Ember app structure and componentization</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_interactivity_events_state\">Ember interactivity: Events, classes and state</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_conditional_footer\">Ember Interactivity: Footer functionality, conditional rendering</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_routing\">Routing in Ember</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Ember_resources\">Ember resources and troubleshooting</a></li></ol></details></li><li><details><summary>Vue</summary><ol><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_getting_started\">开始使用 Vue</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_first_component\">创建第一个 Vue 组件</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_rendering_lists\">渲染 Vue 组件列表</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_methods_events_models\">使用 Vue event、method 和 model 添加一个新的 todo 表单</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_styling\">使用 CSS 为 Vue 组件添加样式</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_computed_properties\">Vue 中的计算属性</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_conditional_rendering\">Vue 中的条件渲染：编辑现有的待办事项</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_refs_focus_management\">使用 Vue 模板引用进行焦点管理</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Vue_resources\">Vue 资源</a></li></ol></details></li><li><details><summary>Svelte</summary><ol><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_getting_started\">Svelte 入门</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_Todo_list_beginning\">开始编写我们的 Svelte 待办事项列表应用程序</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_variables_props\">Svelte 中的动态行为：变量和属性</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_components\">将我们的 Svelte 应用组件化</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_reactivity_lifecycle_accessibility\">Svelte 进阶：响应式、生命周期以及无障碍</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_stores\">使用 Svelte store</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_TypeScript\">Svelte 对 TypeScript 的支持</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Svelte_deployment_next\">部署以及下一步</a></li></ol></details></li><li><details><summary>Angular</summary><ol><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_getting_started\">Angular 入门</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_todo_list_beginning\">Beginning our Angular todo list app</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_styling\">Styling our Angular app</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_item_component\">Creating an item component</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_filtering\">Filtering our to-do items</a></li><li><a class=\"only-in-en-us\" title=\"此页面目前仅提供英文版本\" href=\"/en-US/docs/Learn/Tools_and_testing/Client-side_JavaScript_frameworks/Angular_building\">Building Angular applications and further resources</a></li></ol></details></li><li><details><summary>Git 和 GitHub</summary><ol><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/GitHub\">Git 和 GitHub</a></li></ol></details></li><li><details><summary>跨浏览器测试</summary><ol><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing\">跨浏览器测试</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Introduction\">跨浏览器测试介绍</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Testing_strategies\">测试的策略</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/HTML_and_CSS\">处理常见的 HTML 和 CSS 问题</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/JavaScript\">处理常见的 JavaScript 问题</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Accessibility\">解决常见的无障碍问题</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Feature_detection\">实现特性检测</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Automated_testing\">自动化测试简介</a></li><li><a href=\"/zh-CN/docs/Learn/Tools_and_testing/Cross_browser_testing/Your_own_automation_environment\">搭建自己的自动化测试环境</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/Server-side\">服务端网页编程</a></li><li><details><summary>第一步</summary><ol><li><a href=\"/zh-CN/docs/Learn/Server-side/First_steps\">服务端网站编程的第一步</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/First_steps/Introduction\">服务端编程介绍</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/First_steps/Client-Server_overview\">客户端服务端交互概述</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/First_steps/Web_frameworks\">服务端 web 框架</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/First_steps/Website_security\">站点安全</a></li></ol></details></li><li><details><summary>Django Web 框架（Python）</summary><ol><li><a href=\"/zh-CN/docs/Learn/Server-side/Django\">Django Web 框架 (python)</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Introduction\">Django 介绍</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/development_environment\">设置 Django 开发环境</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Tutorial_local_library_website\">Django Tutorial: The Local Library website</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/skeleton_website\">Django Tutorial Part 2: 创建网站的地基</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Models\">Django Tutorial Part 3: 使用模型</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Admin_site\">Django Tutorial Part 4: Django 管理员站点</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Home_page\">Django 教程 5：主页构建</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Generic_views\">Django 教程 6: 通用列表和详细信息视图</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Sessions\">Django 教程 7: 会话框架</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Authentication\">Django 教程 8：用户授权与许可</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Forms\">Django 教程 9: 使用表单</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Testing\">Django 教程 10: 测试 Django 网页应用</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/Deployment\">Django 教程 11：部署 Django 到生产环境</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/web_application_security\">Django Web 应用安全</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Django/django_assessment_blog\">评估：DIY Django 微博客</a></li></ol></details></li><li><details><summary>Express Web 框架（Node.js/JavaScript）</summary><ol><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs\">Express Web 框架（Node.js/JavaScript）</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/Introduction\">Express/Node 入门</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/development_environment\">设置 Node 开发环境</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/Tutorial_local_library_website\">Express 教程：本地图书馆网站</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/skeleton_website\">Express 教程 2：创建站点框架</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/mongoose\">Express 教程 3：使用数据库 (Mongoose)</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/routes\">Express 教程 4：路由和控制器</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/Displaying_data\">Express 教程 5: 呈现图书馆数据</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/forms\">Express 教程 6: 使用表单</a></li><li><a href=\"/zh-CN/docs/Learn/Server-side/Express_Nodejs/deployment\">Express 教程 7: 部署到生产环境</a></li></ol></details></li><li class=\"section\"><a href=\"/zh-CN/docs/Learn/Common_questions\">更多资源</a></li><li><details><summary>常见问题</summary><ol><li><a href=\"/zh-CN/docs/Learn/Common_questions\">常见问题</a></li><li><a href=\"/zh-CN/docs/Learn/HTML/Howto\">使用 HTML 解决常见问题</a></li><li><a href=\"/zh-CN/docs/Learn/CSS/Howto\">解决常见的 CSS 问题</a></li><li><a href=\"/zh-CN/docs/Learn/JavaScript/Howto\">解决 JavaSctript 代码的常见问题</a></li><li><a href=\"/zh-CN/docs/Learn/Common_questions/Web_mechanics\">Web 机制</a></li><li><a href=\"/zh-CN/docs/Learn/Common_questions/Tools_and_setup\">工具和安装</a></li><li><a href=\"/zh-CN/docs/Learn/Common_questions/Design_and_accessibility\">设计与无障碍</a></li></ol></details></li></ol>","sidebarMacro":"LearnSidebar","body":[{"type":"prose","value":{"id":null,"title":null,"isH3":false,"content":"<ul class=\"prev-next\">\n <li><a class=\"button secondary\" href=\"/zh-CN/docs/Learn/MathML/First_steps/Fractions_and_roots\"><span class=\"button-wrap\"> 上一页 </span></a></li>\n <li><a class=\"button secondary\" href=\"/zh-CN/docs/Learn/MathML/First_steps\"><span class=\"button-wrap\"> 概述：MathML 入门概述</span></a></li>\n <li><a class=\"button secondary\" href=\"/zh-CN/docs/Learn/MathML/First_steps/Tables\"><span class=\"button-wrap\"> 下一页 </span></a></li>\n</ul>\n<p>我们继续回顾基本数学符号，并重点介绍如何使用附加符号构建 MathML 元素。</p>\n<figure class=\"table-container\"><table>\n <tbody>\n <tr>\n <th scope=\"row\">前提：</th>\n <td>\n 基本的计算机操作能力、<a href=\"/zh-CN/docs/Learn/Getting_started_with_the_web/Installing_basic_software\">安装基本软件</a>、<a href=\"/zh-CN/docs/Learn/Getting_started_with_the_web/Dealing_with_files\">处理文件</a>的基本知识，以及\n HTML 基础知识（可以学习 <a href=\"/zh-CN/docs/Learn/HTML/Introduction_to_HTML\">HTML 入门</a>。）\n </td>\n </tr>\n <tr>\n <th scope=\"row\">目标：</th>\n <td>熟悉基本的 MathML 上下标元素。</td>\n </tr>\n </tbody>\n</table></figure>"}},{"type":"prose","value":{"id":"下标和上标","title":"下标和上标","isH3":false,"content":"<p>类似于我们在<a href=\"/zh-CN/docs/Learn/MathML/First_steps/Fractions_and_roots\">上一篇文章</a>中所学习的，<code><msub></code>、<code><msup></code> 和 <code><msubsup></code> 具有特殊的结构，它们恰好有两个元素（<code><msub></code>、<code><msup></code>）或三个元素（<code><msubsup></code>）：</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html notranslate\"><code><p>\n msub:\n <math>\n <msub>\n <mtext>child1</mtext>\n <mtext>child2</mtext>\n </msub>\n </math>\n</p>\n\n<p>\n msup:\n <math>\n <msup>\n <mtext>child1</mtext>\n <mtext>child2</mtext>\n </msup>\n </math>\n</p>\n<p>\n msubsup:\n <math>\n <msubsup>\n <mtext>child1</mtext>\n <mtext>child2</mtext>\n <mtext>child3</mtext>\n </msubsup>\n </math>\n</p>\n</code></pre></div>\n<p>以下是在你的浏览器中的上述示例的渲染结果。</p><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"下标和上标 sample\" id=\"frame_下标和上标\" width=\"700\" height=\"200\" src=\"about:blank\" data-live-path=\"/zh-CN/docs/Learn/MathML/First_steps/Scripts\" data-live-id=\"下标和上标\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>可以看出：</p>\n<ul>\n <li><code><msub></code> 元素的第二个子元素作为其第一个子元素的下标附加。</li>\n <li><code><msup></code> 元素的第二个子元素作为其第一个子元素的上标附加。</li>\n <li><code><msubsup></code> 元素的第二个和第三个子元素分别作为其第一个子元素的下标和上标附加。</li>\n <li>上下标内的文本会缩小显示。</li>\n</ul>\n<div class=\"notecard note\">\n <p><strong>备注：</strong>MathML 元素 <code><msub></code> 和 <code><msup></code> 与 HTML 元素 <a href=\"/zh-CN/docs/Web/HTML/Element/sub\"><code><sub></code></a> 和 <a href=\"/zh-CN/docs/Web/HTML/Element/sup\"><code><sup></code></a> 不同。它们允许开发者将任意的 MathML 子树作为附加符号，而不仅仅是文本。</p>\n</div>"}},{"type":"prose","value":{"id":"正下标和正上标","title":"正下标和正上标","isH3":false,"content":"<p><code><munder></code>、<code><mover></code> 和 <code><munderover></code> 元素与之前介绍的元素非常相似，只是它们用于附加正下标（underscript）和正上标（overscirpt）。我们不会提供详细信息，而是让你自己通过以下练习来了解它们的定义。</p>"}},{"type":"prose","value":{"id":"主动学习：识别正下标和正上标","title":"主动学习：识别正下标和正上标","isH3":true,"content":"<p>在下面的示例中，试着猜测神秘元素的名称（用问号表示），然后点击按钮来显示答案：</p>\n<div class=\"code-example\"><pre class=\"brush: html hidden notranslate\"><code><p>\n <code>&lt;<span>????????</span>&gt;</code>\n 元素正好具有两个子元素（child1、child2）：\n <math>\n <mover>\n <mtext>child1</mtext>\n <mtext>child2</mtext>\n </mover>\n </math>\n</p>\n<p>\n <code>&lt;<span>????????</span>&gt;</code>\n 元素正好具有三个子元素（child1、child2 以及 child3）：\n <math>\n <munderover>\n <mtext>child1</mtext>\n <mtext>child2</mtext>\n <mtext>child3</mtext>\n </munderover>\n </math>\n</p>\n<p>\n <code>&lt;<span>????????</span>&gt;</code>\n 元素正好具有两个子元素（child1、child2）：\n <math>\n <munder>\n <mtext>child1</mtext>\n <mtext>child2</mtext>\n </munder>\n </math>\n</p>\n\n<p><input type=\"button\" id=\"showSolution\" value=\"展示结果\" /></p>\n</code></pre></div>\n<div class=\"code-example\"><pre class=\"brush: css hidden notranslate\"><code>p {\n padding: 0.5em;\n}\n</code></pre></div>\n<div class=\"code-example\"><pre class=\"brush: js hidden notranslate\"><code>document.getElementById(\"showSolution\").addEventListener(\"click\", () => {\n const maths = Array.from(document.getElementsByTagName(\"math\"));\n Array.from(document.getElementsByTagName(\"span\")).forEach((span, index) => {\n span.textContent = maths[index].firstElementChild.tagName;\n });\n});\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"主动学习：识别正下标和正上标 sample\" id=\"frame_主动学习：识别正下标和正上标\" width=\"700\" height=\"400\" src=\"about:blank\" data-live-path=\"/zh-CN/docs/Learn/MathML/First_steps/Scripts\" data-live-id=\"主动学习：识别正下标和正上标\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>"}},{"type":"prose","value":{"id":"主动学习：识别附加符号元素","title":"主动学习：识别附加符号元素","isH3":true,"content":"<p>以下的 MathML 公式包含了更复杂的表达式，嵌套了分数、根号和附加符号元素。尝试猜测使用了 <code><msub></code>、<code><msup></code>、<code><msubsup></code>、<code><munder></code>、<code><mover></code>、<code><munderover></code> 的元素。每次当你点击这样的元素时，它会被突出显示，并显示确认信息。最后，阅读 MathML 源代码以验证是否与你的预期相符。</p>\n<div class=\"code-example\"><pre class=\"brush: html hidden notranslate\"><code><!doctype html>\n<html lang=\"en-US\">\n <head>\n <meta charset=\"utf-8\" />\n <title>带有附加符号元素的页面</title>\n <link\n rel=\"stylesheet\"\n href=\"https://fred-wang.github.io/MathFonts/LatinModern/mathfonts.css\" />\n </head>\n <body>\n <math display=\"block\">\n <mroot>\n <mrow>\n <munder>\n <mi>β</mi>\n <mo>⎵</mo>\n </munder>\n </mrow>\n <mn>3</mn>\n </mroot>\n <mo>+</mo>\n <mfrac>\n <mrow\n ><mo>|</mo>\n <mover>\n <mi>α</mi>\n <mo>→</mo>\n </mover>\n <mo>|</mo>\n </mrow>\n <msup>\n <mi>s</mi>\n <mn>3</mn>\n </msup>\n </mfrac>\n <mo>−</mo>\n <mrow>\n <munderover>\n <mo>∑</mo>\n <mrow>\n <mi>i</mi>\n <mo>=</mo>\n <mn>1</mn>\n </mrow>\n <mi>n</mi>\n </munderover>\n <msqrt>\n <mrow>\n <msub>\n <mi>a</mi>\n <mi>i</mi>\n </msub>\n <mo>−</mo>\n <msubsup>\n <mi>K</mi>\n <mn>0</mn>\n <mi>i</mi>\n </msubsup>\n </mrow>\n </msqrt>\n </mrow>\n </math>\n <input type=\"button\" id=\"clearOutput\" value=\"重置\" />\n <div id=\"output\"></div>\n </body>\n</html>\n</code></pre></div>\n<div class=\"code-example\"><pre class=\"brush: css hidden notranslate\"><code>.highlight {\n color: red;\n}\nmath {\n font-size: 200%;\n}\n</code></pre></div>\n<div class=\"code-example\"><pre class=\"brush: js hidden notranslate\"><code>const scriptedElements = Array.from(\n document.querySelectorAll(\"msub, msup, msubsup, munder, mover, munderover\"),\n);\nconst outputDiv = document.getElementById(\"output\");\nfunction clearHighlight() {\n scriptedElements.forEach((scripted) => {\n scripted.classList.remove(\"highlight\");\n });\n}\nscriptedElements.forEach((scripted) => {\n scripted.addEventListener(\"click\", () => {\n clearHighlight();\n scripted.classList.add(\"highlight\");\n outputDiv.insertAdjacentHTML(\n \"beforeend\",\n `<p><strong>你点击了 <code>&lt;${scripted.tagName}&gt;</code> 元素。</strong></p>`,\n );\n });\n});\ndocument.getElementById(\"clearOutput\").addEventListener(\"click\", () => {\n clearHighlight();\n outputDiv.innerHTML = \"\";\n});\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"主动学习：识别附加符号元素 sample\" id=\"frame_主动学习：识别附加符号元素\" width=\"700\" height=\"400\" src=\"about:blank\" data-live-path=\"/zh-CN/docs/Learn/MathML/First_steps/Scripts\" data-live-id=\"主动学习：识别附加符号元素\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>"}},{"type":"prose","value":{"id":"其他运算符属性","title":"其他运算符属性","isH3":false,"content":"<p>我们之前已经了解了 <code><mo></code> 元素的一些<a href=\"/zh-CN/docs/Learn/MathML/First_steps/Text_containers#mo_%E7%9A%84%E8%BF%90%E7%AE%97%E7%AC%A6%E5%B1%9E%E6%80%A7\">属性</a>，包括在垂直方向上的拉伸和间距。现在有了附加符号元素，我们可以扩展该列表。我们将通过修改我们的<a href=\"#%E4%B8%BB%E5%8A%A8%E5%AD%A6%E4%B9%A0%EF%BC%9A%E8%AF%86%E5%88%AB%E9%99%84%E5%8A%A0%E7%AC%A6%E5%8F%B7%E5%85%83%E7%B4%A0\">上一个示例</a>来实现这一点。</p>"}},{"type":"prose","value":{"id":"在水平方向上的拉伸","title":"在水平方向上的拉伸","isH3":true,"content":"<p>首先，让我们进行以下替换：\n <math>\n <mi>β</mi>\n <mo>≔</mo>\n <mrow>\n <msub>\n <mi>z</mi>\n <mn>1</mn>\n </msub>\n <mo>+</mo>\n <msub>\n <mi>z</mi>\n <mn>2</mn>\n </msub>\n </mrow>\n </math> 和 \n <math>\n <mi>α</mi>\n <mo>≔</mo>\n <mrow>\n <msub>\n <mi>v</mi>\n <mn>1</mn>\n </msub>\n <mo>+</mo>\n <msub>\n <mi>v</mi>\n <mn>2</mn>\n </msub>\n </mrow>\n </math>：\n</p>\n<div class=\"code-example\"><pre class=\"brush: html hidden notranslate\"><code><!doctype html>\n<html lang=\"zh-CN\">\n <head>\n <meta charset=\"utf-8\" />\n <title>带有水平拉伸操作符的页面</title>\n <link\n rel=\"stylesheet\"\n href=\"https://fred-wang.github.io/MathFonts/LatinModern/mathfonts.css\" />\n </head>\n <body>\n <math display=\"block\">\n <mroot>\n <mrow>\n <munder>\n <mrow>\n <msub>\n <mi>z</mi>\n <mn>1</mn>\n </msub>\n <mo>+</mo>\n <msub>\n <mi>z</mi>\n <mn>2</mn>\n </msub>\n </mrow>\n <mo>⎵</mo>\n </munder>\n </mrow>\n <mn>3</mn>\n </mroot>\n <mo>+</mo>\n <mfrac>\n <mrow\n ><mo>|</mo>\n <mover>\n <mrow>\n <msub>\n <mi>v</mi>\n <mn>1</mn>\n </msub>\n <mo>+</mo>\n <msub>\n <mi>v</mi>\n <mn>2</mn>\n </msub>\n </mrow>\n <mo>→</mo>\n </mover>\n <mo>|</mo>\n </mrow>\n <msup>\n <mi>s</mi>\n <mn>3</mn>\n </msup>\n </mfrac>\n <mo>−</mo>\n <mrow>\n <munderover>\n <mo>∑</mo>\n <mrow>\n <mi>i</mi>\n <mo>=</mo>\n <mn>1</mn>\n </mrow>\n <mi>n</mi>\n </munderover>\n <msqrt>\n <mrow>\n <msub>\n <mi>a</mi>\n <mi>i</mi>\n </msub>\n <mo>−</mo>\n <msubsup>\n <mi>K</mi>\n <mn>0</mn>\n <mi>i</mi>\n </msubsup>\n </mrow>\n </msqrt>\n </mrow>\n </math>\n </body>\n</html>\n</code></pre></div>\n<div class=\"code-example\"><pre class=\"brush: css hidden notranslate\"><code>.highlight {\n color: red;\n}\nmath {\n font-size: 200%;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"在水平方向上的拉伸 sample\" id=\"frame_在水平方向上的拉伸\" width=\"700\" height=\"200\" src=\"about:blank\" data-live-path=\"/zh-CN/docs/Learn/MathML/First_steps/Scripts\" data-live-id=\"在水平方向上的拉伸\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>可以看出底部括号“⎵”和右箭头“→”在水平方向上会延伸以覆盖被替代值的宽度。回想一下，<a href=\"/zh-CN/docs/Learn/MathML/First_steps/Text_containers#active_learning_stretchy_operators\">一些竖直运算符可以伸展</a>，以覆盖 <code><mrow></code> 中非伸展兄弟节点的高度。类似地，一些水平运算符可以伸展以覆盖 <code><munder></code>、<code><mover></code> 或 <code><munderover></code> 元素中非伸展兄弟节点的宽度。</p>\n<div class=\"notecard note\">\n <p><strong>备注：</strong>伸展适用于 <code><munder></code>、<code><mover></code> 或 <code><munderover></code> 元素的任何子元素，不仅仅是正下标或正上标。</p>\n</div>"}},{"type":"prose","value":{"id":"大型运算符和极限","title":"大型运算符和极限","isH3":true,"content":"<p>到目前为止，我们的示例实际上是使用 <a href=\"/zh-CN/docs/Learn/MathML/First_steps/Getting_started#display_%E5%B1%9E%E6%80%A7\"><code>display=\"block\"</code></a> 属性呈现的。让我们看一下同一个示例，在没有该属性的情况下渲染的效果：</p>\n<div class=\"code-example\"><pre class=\"brush: html hidden notranslate\"><code><!doctype html>\n<html lang=\"zh-CN\">\n <head>\n <meta charset=\"utf-8\" />\n <title>极限符号被挪动并且大型运算符变小的页面</title>\n <link\n rel=\"stylesheet\"\n href=\"https://fred-wang.github.io/MathFonts/LatinModern/mathfonts.css\" />\n </head>\n <body>\n <math>\n <mroot>\n <mrow>\n <munder>\n <mrow>\n <msub>\n <mi>z</mi>\n <mn>1</mn>\n </msub>\n <mo>+</mo>\n <msub>\n <mi>z</mi>\n <mn>2</mn>\n </msub>\n </mrow>\n <mo>⎵</mo>\n </munder>\n </mrow>\n <mn>3</mn>\n </mroot>\n <mo>+</mo>\n <mfrac>\n <mrow\n ><mo>|</mo>\n <mover>\n <mrow>\n <msub>\n <mi>v</mi>\n <mn>1</mn>\n </msub>\n <mo>+</mo>\n <msub>\n <mi>v</mi>\n <mn>2</mn>\n </msub>\n </mrow>\n <mo>→</mo>\n </mover>\n <mo>|</mo>\n </mrow>\n <msup>\n <mi>s</mi>\n <mn>3</mn>\n </msup>\n </mfrac>\n <mo>−</mo>\n <mrow>\n <munderover>\n <mo>∑</mo>\n <mrow>\n <mi>i</mi>\n <mo>=</mo>\n <mn>1</mn>\n </mrow>\n <mi>n</mi>\n </munderover>\n <msqrt>\n <mrow>\n <msub>\n <mi>a</mi>\n <mi>i</mi>\n </msub>\n <mo>−</mo>\n <msubsup>\n <mi>K</mi>\n <mn>0</mn>\n <mi>i</mi>\n </msubsup>\n </mrow>\n </msqrt>\n </mrow>\n </math>\n </body>\n</html>\n</code></pre></div>\n<div class=\"code-example\"><pre class=\"brush: css hidden notranslate\"><code>.highlight {\n color: red;\n}\nmath {\n font-size: 200%;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"大型运算符和极限 sample\" id=\"frame_大型运算符和极限\" width=\"700\" height=\"200\" src=\"about:blank\" data-live-path=\"/zh-CN/docs/Learn/MathML/First_steps/Scripts\" data-live-id=\"大型运算符和极限\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>不出所料，公式不再居中，渲染方式发生变动，导致高度最小化。注意求和符号，可以看到求和符号变小了，并且 <code><munderover></code> 元素的附加符号现在以下标和上标的方式附加在其上！这是由于“∑”运算符的两个属性：</p>\n<ul>\n <li><em>largeop</em>：如果 <code><math></code> 标签具有 <code>display=\"block\"</code> 属性，则使用更大的字形绘制运算符。</li>\n <li><em>movablelimits</em>：如果 <code><math></code> 标签没有 <code>display=\"block\"</code> 属性，则将附加在运算符上的正下标和正上标分别渲染为下标和上标。</li>\n</ul>\n<div class=\"notecard note\">\n <p><strong>备注：</strong> <em>largeop</em> 属性实际上与附加符号无关，尽管具有此属性的运算符通常会有附加符号。<em>movablelimits</em> 属性也适用于 <code><munder></code> 和 <code><mover></code> 元素。</p>\n</div>"}},{"type":"prose","value":{"id":"总结","title":"总结","isH3":false,"content":"<p>在本文中，我们完成了对引入下标、上标、正下标和正上标的基本布局元素 <code><msub></code>、<code><msup></code>、<code><msubsup></code>、<code><munder></code>、<code><mover></code> 以及 <code><munderover></code> 的介绍。在介绍这些元素的过程中，我们顺便介绍了 <code><mo></code> 元素的新属性。在下一篇文章中，我们将继续关注<a href=\"/zh-CN/docs/Learn/MathML/First_steps/Tables\">表格布局</a>。</p><ul class=\"prev-next\">\n <li><a class=\"button secondary\" href=\"/zh-CN/docs/Learn/MathML/First_steps/Fractions_and_roots\"><span class=\"button-wrap\"> 上一页 </span></a></li>\n <li><a class=\"button secondary\" href=\"/zh-CN/docs/Learn/MathML/First_steps\"><span class=\"button-wrap\"> 概述：MathML 入门概述</span></a></li>\n <li><a class=\"button secondary\" href=\"/zh-CN/docs/Learn/MathML/First_steps/Tables\"><span class=\"button-wrap\"> 下一页 </span></a></li>\n</ul>"}},{"type":"prose","value":{"id":"参见","title":"参见","isH3":false,"content":"<ul>\n <li><a href=\"/zh-CN/docs/Web/MathML/Element/msub\"><msub>元素</msub></a></li>\n <li><a href=\"/zh-CN/docs/Web/MathML/Element/msup\"><msup>元素</msup></a></li>\n <li><a href=\"/zh-CN/docs/Web/MathML/Element/msubsup\"><msubsup>元素</msubsup></a></li>\n <li><a href=\"/zh-CN/docs/Web/MathML/Element/munder\"><munder>元素</munder></a></li>\n <li><a href=\"/zh-CN/docs/Web/MathML/Element/mover\"><mover>元素</mover></a></li>\n <li><a href=\"/zh-CN/docs/Web/MathML/Element/munderover\"><munderover>元素</munderover></a></li>\n</ul>"}}],"toc":[{"text":"下标和上标","id":"下标和上标"},{"text":"正下标和正上标","id":"正下标和正上标"},{"text":"其他运算符属性","id":"其他运算符属性"},{"text":"总结","id":"总结"},{"text":"参见","id":"参见"}],"summary":"我们继续回顾基本数学符号，并重点介绍如何使用附加符号构建 MathML 元素。","popularity":0,"modified":"2024-07-26T12:09:17.000Z","other_translations":[{"locale":"de","title":"MathML gescriptete Elemente","native":"Deutsch"},{"locale":"en-US","title":"MathML scripted elements","native":"English (US)"},{"locale":"ja","title":"MathML 添字要素","native":"日本語"}],"pageType":"unknown","source":{"folder":"zh-cn/learn/mathml/first_steps/scripts","github_url":"https://github.com/mdn/translated-content/blob/main/files/zh-cn/learn/mathml/first_steps/scripts/index.md","last_commit_url":"https://github.com/mdn/translated-content/commit/2d338d1e57af1fb39db4bf0b6064e20d8c77295e","filename":"index.md"},"short_title":"MathML 附加符号","parents":[{"uri":"/zh-CN/docs/Learn","title":"学习 Web 开发"},{"uri":"/zh-CN/docs/Learn/MathML","title":"使用 MathML 编写数学公式"},{"uri":"/zh-CN/docs/Learn/MathML/First_steps","title":"MathML 入门概述"},{"uri":"/zh-CN/docs/Learn/MathML/First_steps/Scripts","title":"MathML 附加符号"}],"pageTitle":"MathML 附加符号 - 学习 Web 开发 | MDN","noIndexing":false}}</script></body></html>