I receive HTML pages from our creative team, and then use those to build aspx pages. One challenge I frequently face is getting the HTML I spit out to match theirs exactly.
If out output XML compliant HTML. Or at least translate your HTML product into XML compliancy, you at least could then XSL your output to remove the content and id tags. Apply the same transformation to their html, and then compare.
winmerge is a good visual diff program
A copy of my own answer from here.
What about DaisyDiff (Java and PHP vesions available).
Following features are really nice:
You can use HTMLTidy to convert the HTML to well-formed XML so you can use XML Diff, as Gulzar suggested.
tidy -asxml index.html
I was thinking on lines of XML Diff since HTML can be represented as an XML Document. The challenge with HTML is that it might not be always well formed. Found one more here showing how to use XMLDiff class.