Originally Posted by sunfighter
felgall I spent this morning looking up and reading the "are closing tags legal in html5" articles on the web.
You misread what I wrote - I said that they are valid (in fact they are required) in X
HTML5 - I agree that they are invalid in HTML 5 just as they are invalid in HTML4. A lot of people use them in HTML 4/5 because they intend to switch over to XHTML once everyone uses browsers that support it (just waiting for IE8 to die and then XHTML will be useable). The XHTML5 spec is being developed in parallel to HTML 5 so that they will be as close to the same as possible with the closing slashes being one of the few necessary differences.
Both HTML 5 and XHTML 5 use the same doctype since the doctype has never told the browser whether the page is using HTML or XHTML separate ones are unnecessary - browsers have always used the MIME type to determine whether the page is HTML or XHTML.