Upgrades of W3C Quality Tools W3C Markup Validator
Also known as the 'HTML validator', the newest version of the W3C markup validation service includes usability enhancements, improved feedback, support for installation on Windows, and better support for both W3C and non-W3C document types. This popular free service can dramatically help improving and ensuring the quality of Web sites, therefore saving time and money. The Markup validator is an open source/free software, available for download and installation on a variety of systems and platforms.
The CSS Validation Service has also been updated. Changes include a stable SOAP access and output to the CSS validator, the addition of a profile for the CSS 2.1 specification, and a large number of bug fixes.
A new upgrade of the log validator was released earlier this month. The Log Validator makes it easy to manage the quality of even large Web Sites, step by step, by finding the most popular documents failing Markup or CSS validation, or with broken links.
W3C Markup Validator: http://validator.w3.org
W3C CSS Validator: http://jigsaw.w3.org/css-validator/
W3C Log Validator: http://www.w3.org/QA/Tools/LogValidator/