Problem
You want to create an HTML5 page.
Solution
Specify the HTML5 DOCTYPE at the very beginning of your page:
<!DOCTYPE html>
<html>
<head>
<title>HTML5, for Fun & Profit</title>
</head>
<body>
</body>
</html>
Note that the DOCTYPE is not case-sensitive. Feel free to go CaMeL
cAsE with the characters..
Discussion
The Document Type Definition, or DOCTYPE, tells browsers and validators what version of HTML the page is written in. Previous versions of HTML specified the version number, such as the DOCTYPE for XHTML 1.0 Strict:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.With HTML5, the version is dropped from the DOCTYPE.
This allows HTML5 to be backwards compatible in terms of syntax and, hopefully, makes the transition toHTML5 easier.
Let’s say you have a site that is valid HTML 4.0, but you want to transition to HTML5. Start with just the DOCTYPE change, and you not only have a valid site, but also a valid HTML5 site.
Additionally, all browsers recognize the shortened DOCTYPE and render in strict standards mode. There are some elements that have changed between HTML4 and HTML5, so some now removed or deprecated parts of your HTML4 document.
For example, <center>) might not technically validate as HTML5.