Validating your HTML will help insure that it displays properly on all browsers. Most of these tool read your web pages directly from your site. A few are perl scripts which must be uploaded to your site and ran from there. To fully understand each tool's indications you can refer to the book on the right: Elizabeth Castro's "HTML 4 for the World Wide Web, Visual QuickStart Guide" is perhaps the best introductive book about HTML. But here are the best HTML validator:
Bobby http://www.cast.org/bobby Bobby is the most popular HTML validator. Bobby checks that your HTML is valid for numerous popular browsers as well as checking that your page is accessible for people with disabilities. Bobby limits the number of pages it checks in order to keep the server available to all. To test an entire site as a batch, use the downloadable version of Bobby. Bobby was created by CAST (Center for Applied Special Technology).
UsableNet - Lift www.usablenet.com This on line tool is based on LIFT Online Free Trial. It will download 5 pages starting from the specified page (URL), and it will test them against a subset of usability and accessibility guidelines (rules), and then will send you an email with the link to your usability report online. LIFT Online Free Trial applies a subset of rules chosen from the 70+ available in the full service.
HTMLValidator www.htmlvalidator.com CSE 3310 HTML Validator. A very nice Windows based HTML validator. This validator can integrate with several popular HTML editors.
