XHTML is the future!
quote:
http://www.w3.org/TR/xhtml1/#xhtml
The XHTML family is the next step in the evolution of the Internet. By migrating to XHTML today, content developers can enter the XML world with all of its attendant benefits, while still remaining confident in their content's backward and future compatibility.
MyBB was originally
not XHTML, and is in the process of being "upgraded." When I create new things, I use XHTML, and I check it with an XHTML validator.
quote:
Originally posted by CookieRevised
For non-empty elements, end tags are required in XHTML. This means you can't use:
<p>this is a line<p>this is a new line.
That's shitty anyway... you should always close your tags if you want clean, professional code.
/ 
