Mark Pilgrim’s overview of HTML 5 form elements includes the following:
I love how easily I can traverse an HTML document with jQuery, and I’d love to be able to do it in PHP. There are a few classes, but the PHP binding for Tidy seems to be where it’s at. The Zend dev pages make it look that way, anyway.
HTML and PostScript are both page description languages, but one is designed to convey the look of the page, while the other to convey the meaning of its content.