w3schools 系列教程之 HTML 介绍_html/css_WEB-ITnose
HTML 是一种描述 Web 文档（页面）的标记语言。
- HTML 代表超文本标记语言（Hyper Text Markup Language）
- 标记语言就是一组标记标签
- HTML 文档是由 HTML 标签来描述的
- 每个 HTML 标记描述了不同的文档内容
HTML 示例代码
<!DOCTYPE html><html> <head> <title>Page Title</title> </head> <body> <h1 id="My-First-Heading">My First Heading</h1> <p>My first paragraph.</p> </body></html>
示例代码解释
- DOCTYPE 声明定义将 HTML 文档类型
- 和 标签之间的文本描述了一个 HTML 文档
- 和 标签之间的文本提供了有关 HTML 文档的信息
-
和 标签之间的文本提供了有关 HTML 文档的标题 - 和 标签之间的文本描述了可见的 HTML 文档内容
-
和
标签之间的文本描述了标题 -
和
标签之间的文本描述了段落
通过使用这些描述，浏览器可以显示一个 HTML 文档的标题和段落。
HTML 标签
HTML 标签是包含了一对尖角号的关键词（标签名称）：
<tagname>content</tagname>
- HTML 标签通常是成对的，比如
和
- 一对标签中的第一个标签是开始标签，第二个是结束标签
- 结束标签像开始标签一样编写，只是在标签名称的前面有一个斜杠
开始标签也可以叫做打开标签，结束标签也可以叫做关闭标签。
Web 浏览器
一个 Web 浏览器的作用是读取并显示一个 HTML 文档。一个 Web 浏览器不显示 HTML 标签，而是通过它们来确定如何显示 HTML 文档。
HTML 页面结构
下面是一个 HTML 页面结构的示例：
<html> <head> <title>Page title</title> </head> <body> <h1 id="This-is-a-heading">This is a heading</h1> <p>This is a paragraph.</p> <p>This is another paragraph.</p> </body></html>
浏览器只显示
标签区域内的内容。声明
声明有助于浏览器能够正确地显示 HTML 页面。
网络中具有不同的文档类型。
想要正确地显示 HTML 文档，浏览器必须要知道 HTML 文档的类型和版本。
声明是不区分大小写的，以下所有写法都是正确地：
<!DOCTYPE html><!DOCTYPE HTML><!doctype html><!Doctype Html>
常见声明
HTML5
<!DOCTYPE html>
HTML 4.01
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
XHTML 1.0
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
HTML 版本
在网络的早期，HTML 就具有了很多版本：
| 版本 | 年份 |
|---|---|
| HTML | 1991 |
| HTML 2.0 | 1995 |
| HTML 3.2 | 1997 |
| HTML 4.01 | 1999 |
| XHTML | 2000 |
| HTML5 | 2014 |
本文翻译于《w3schools》网站提供的 HTML 教程。
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