How do I validate site markup [HTML/CSS] behind a firewall?

Question

I am designing a web site but it is behind a firewall and such services like http://validator.w3.org/ will not work.

Are there any free apps I could run on Windows or Mac OS X that will validate html and css?

Answer 1

Use the HTML Validator plugin for Firefox

http://users.skynet.be/mgueury/mozilla/download.html

It will even work on HTML files on your PC

Answer 2

Note that the (X)HTML validator also has Validate by File Upload and Validate by Direct Input options. The CSS validator has a similar set of options. It would be trivial to write a script that validated automatically using one of those methods.

Answer 3

the w3 validator does have a 'validate by direct input' option (which I use constantly) however TravisO's answer is worthy as the chosen answer :)

Answer 4

Note also that the W3C HTML Validator is Open Source Software and the source is available at HTML Validator Source

Answer 5

The Web Developer Toolbar for Firefox has "Validate Local HTML" under the Tools menu, which does exactly that. And that's only one of about 457 reasons to install the Web Developer Toolbar.