Except that your example is valid HTML 4.01/5. Closing tags are optional.<p>Also, "Be conservative in what you emit, and liberal in what you accept" - Postel's Law: <a href="http://en.wikipedia.org/wiki/Robustness_principle" rel="nofollow">http://en.wikipedia.org/wiki/Robustness_principle</a><p>[edit]: I'm incorrect, <i>some</i> closing tags are optional, &#60;/li&#62; being one of them. for HTML5: <a href="http://www.whatwg.org/specs/web-apps/current-work/#generate-implied-end-tags" rel="nofollow">http://www.whatwg.org/specs/web-apps/current-work/#generate-...</a>