This tag is one of the most important parts of any web page. This tag tells the browser how to interpret the page. It
defines which version of HTML/XHTML the page uses. This allows the browser to correctly interpret the code in the page.
The DOCTYPE tag should be the very first line of any web page. It is a single line tag with no closing tag.
There are several different document type definitions. Use the selection box below to view them. The correct syntax for that tag will be placed
in the text-area box for easy copy and paste.
The document type selected when you loaded the page is probably the most commonly used. You can use the other ones, but beware of using any
"strict" definitions. If you are going to, make sure you validate your pages using a strict interpreter.
W3C Online Markup Validation Service