I understand that in order to instruct the browser how to handle HTML page I need to specify a DOCTYPE... For a page that i built with HTML5 I used the following:
<html dir="ltr" xmlns="http://www.w3.org/1999/xhtml">
xmlns attribute is set, it's a XHTML (XHTML5) document.
This indicates a HTML5 document:
HTTP-Header Content-Type: text/html <!DOCTYPE html> <html>
And this indicates a XHTML5 document:
HTTP-Header Content-Type: application/xhtml+xml <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml">
If the webpage is using XHTML5 an does not have the
xmlns attribute, it wont be displayed properly (Firefox would display the XML-DOM instead of the page).