When editing HTML it's easy to make mistakes. Wouldn't it be nice if
there was a simple way to fix these mistakes automatically and tidy up
sloppy editing into nicely layed out markup?  Well now there is thanks
to Hewlett Packard's Dave Raggett. HTML TIDY is a free utility for
doing just that. It also works great on the attrociously hard to read
markup generated by specialized HTML editors and conversion tools, and
can help you identify where you need to pay further attention on
making your pages more accessible to people with disabilities.

Tidy is able to fix up a wide range of problems and to bring to your
attention things that you need to work on yourself. Each item found is
listed with the line number and column so that you can see where the
problem lies in your markup. Tidy won't generate a cleaned up version
when there are problems that it can't be sure of how to handle. These
are logged as "errors" rather than "warnings".

Homepage:
http://www.html-tidy.org/
