This is the most comprehensive list of differences between HTML and XHTML ever written. Some things in the list technically only apply to HTML5, but HTML5 represents reality far more closely than HTML4, so it doesn’t make that much difference.
This is the most comprehensive list of differences between HTML and XHTML ever written. Some things in the list technically only apply to HTML5, but HTML5 represents reality far more closely than HTML4, so it doesn’t make that much difference.