html validator suggestion

I frequently use the html vaidator and I love it when I have one of those
nagging little problems that I cant find easily. Just pop it in the scanner
and it will usually tell me where I goofed. The only problem I have is if
the page has dynamic content that requires a form, cookie, or some other
session data structure to be in place, the validator ends up scanning the
error page.
I could upload the file you say, but if the page is done in cold
fusion/jsp/php and so on, the validator certainly wont like it.
The solution?
Provide a text box that users can copy and paste the html code into
themselves.

Sounds pretty easy and doable to me.
jon