The HTML tag <html> represents the root (start) of an HTML document. It is the container that all other HTML elements are placed.
HTML标签 <html> 表示HTML文档的根（开始）。它是放置所有HTML元素的容器。
Note: that the <html> tag does not contain the <!doctype> declaration. This is because the document type declaration needs to be the very first element of code in a website; furthermore, the declaration is also not an HTML element. Therefore it cannot be inclosed between the <html> tags with other HTML elements.
注意：<html>标签不包含<！doctype>声明。这是因为文档类型声明必须是网站中代码的第一个元素；此外，声明也不是HTML元素。因此，它不能与其他html元素一起包含在标签里。
Syntax 语法:
The HTML tag is written as <html> </html> with all other HTML elements enclosed between the start and end tags. The HTML tag <html> is the first HTML element in an HTML document, and is only preceded by the document type declaration.
HTML标签写为<html> </html>，所有其他HTML元素都包含在开始标签和结束标签之间。HTML标签是HTML文档中的第一个HTML元素，前面只有文档类型声明。
The very first tag within the HTML tag <html> should always be the head tag <head> tag which is then followed by a body tag <body>. Although a website can function without a head tag, it is an important part of any properly formatted website.
HTML标签中的第一个标签应该始终是<head>标签，然后是<body>标签。虽然一个网站可以在没有标题标签的情况下运行，但它是任何格式正确的网站的重要组成部分。
Example例:
