学习要点：
1.HTML5 文档结构
2.文档结构解析
3.元素标签探讨
主讲教师：李炎恢
本章主要先从 HTML5 的文档结构谈起。 这些基础元素确定了 HTML 文档的轮廓以及浏览器的初始环境。几乎所有页面都必须首先键入这些元素。
一．HTML5 文档结构
1.第一步：打开 Sublime Text 3，打开指定文件夹；
2.第二步：保存 index.html 文件到磁盘中，.html 是网页后缀；
3.第三步：开始编写 HTML5 的基本格式。
<!DOCTYPE html> //文档类型声明<html lang="zh-cn"> //表示 HTML 文档开始 <head> //包含文档元数据开始 <meta charset="utf-8"> //声明字符编码 <title>基本结构</title> //设置文档标题 </head> //包含文档元数据结束 <body> //表示 HTML 文档内容 <a href="http://www.baidu.com">百度</a> //一个超链接元素（标签） </body> //表示 HTML</html> //表示 HTML 文档结束
二．文档结构解析
1.Doctype
文档类型声明（Document Type Declaration，也称 Doctype）。它主要告诉浏览器所查看的文件类型。 在以往的 HTML4.01 和XHTML1.0 中， 它表示具体的 HTML 版本和风格。而如今 HTML5 不需要表示版本和风格了。
<!DOCTYPE html> //不分区大小写
2.html 元素
首先，元素就是标签的意思，html 元素即 html 标签。html 元素是文档开始和结尾的元素。它是一个双标签，头尾呼应，包含内容。这个元素有一个属性和值：lang="zh-cn"，表示文档采用语言为：简体中文。
<html lang="zh-cn"> //如果是英文则为 en
3.head 元素
用来包含元数据内容，元数据包括：、、
<head>...</head> //这些信息在页面不可见
4.meta 元素
这个元素用来提供关于文档的信息，起始结构有一个属性为：charset="utf8"。表示告诉浏览器页面采用的什么编码，一般来说我们就用 utf8。当然，文件保存的时候也是utf8，而浏览器也设置 utf8 即可正确显示中文。
<meta charset="utf-8"> //除了设置编码，还有别的
5.title 元素
这个元素很简单，顾名思义：设置浏览器左上角的标题。
<title>基本结构</title>
6.body 元素
用来包含文档内容的元素，也就是浏览器可见区域部分。所有的可见内容，都应该在这个元素内部进行添加。
<body>...</body>
7.a 元素
一个超链接，后面会详细探讨。
<a href="http://www.baidu.com">百度</a>
三．元素标签探讨
HTML 是一种标记语言，刚才的结构我们已经详细探讨过。这里，我们再剖析一下这些“标记”或者叫“标签”，书面上经常称作为“元素”的东西是怎么构成的。
1.元素
元素就是一组告诉浏览器如何处理一些内容的标签。每个元素都有一个关键字，比如
What is the purpose of the <datalist> element?Mar 21, 2025 pm 12:33 PMThe article discusses the HTML <datalist> element, which enhances forms by providing autocomplete suggestions, improving user experience and reducing errors.Character count: 159
How do I use HTML5 form validation attributes to validate user input?Mar 17, 2025 pm 12:27 PMThe article discusses using HTML5 form validation attributes like required, pattern, min, max, and length limits to validate user input directly in the browser.
What is the purpose of the <iframe> tag? What are the security considerations when using it?Mar 20, 2025 pm 06:05 PMThe article discusses the <iframe> tag's purpose in embedding external content into webpages, its common uses, security risks, and alternatives like object tags and APIs.
What is the purpose of the <progress> element?Mar 21, 2025 pm 12:34 PMThe article discusses the HTML <progress> element, its purpose, styling, and differences from the <meter> element. The main focus is on using <progress> for task completion and <meter> for stati
What are the best practices for cross-browser compatibility in HTML5?Mar 17, 2025 pm 12:20 PMArticle discusses best practices for ensuring HTML5 cross-browser compatibility, focusing on feature detection, progressive enhancement, and testing methods.
What is the purpose of the <meter> element?Mar 21, 2025 pm 12:35 PMThe article discusses the HTML <meter> element, used for displaying scalar or fractional values within a range, and its common applications in web development. It differentiates <meter> from <progress> and ex
What is the viewport meta tag? Why is it important for responsive design?Mar 20, 2025 pm 05:56 PMThe article discusses the viewport meta tag, essential for responsive web design on mobile devices. It explains how proper use ensures optimal content scaling and user interaction, while misuse can lead to design and accessibility issues.
How do I use the HTML5 <time> element to represent dates and times semantically?Mar 12, 2025 pm 04:05 PMThis article explains the HTML5 <time> element for semantic date/time representation. It emphasizes the importance of the datetime attribute for machine readability (ISO 8601 format) alongside human-readable text, boosting accessibilit
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
SublimeText3 Chinese version
Chinese version, very easy to use
DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software
PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
Dreamweaver CS6
Visual web development tools
