Introduction to the functions of html doctype_HTML/Xhtml_Web page production

The document mode mainly has the following two functions:

1. Tell the browser what html or xhtml specification to use to parse the html document

2. For the browser Rendering mode has an impact; different rendering modes will affect the browser's parsing of CSS code and even JavaScript scripts, so Doctype is very critical, especially in the IE series browsers, the rendering mode of the HTML page determined by DOCTYPE. It's important.

Two rendering modes:

BackCompat: Standard compatibility mode is not turned on (or called Quirks mode, mixed mode)
CSS1Compat: Standard compatibility Mode is turned on (or called strict mode [Standards mode/Strict mode])