Good HTML parser needed

Hi all,

The fact is that I have a site that allow users to post hypertext articles.
However, I saw that sometimes, because of their careless input,
the articles is not rendered correctly.

I want to know whether there are some good HTML parsers written in PHP.

That is,
the parser checks whether html tags like table, tr, td, div, dt, dl, dd,
script, ul,
li, span, h1, h2, etc. are nested correctly. If any tags not matched, just
remove them.

Any suggection is greatly appreciated.

-- 
Regards,
Shelley