W3C Markup Validation Service, a free service that checks Web documents in formats like HTML and XHTML for conformance to W3C Recommendations and other standards.
a service that allows you to analyze, assess and validate any link using various tools and testers on the web. Rather than creating direct links to various validators and link analyzers, one link can be used to submit to all of them.
Synchronized Multimedia Integration Language, is a W3C Recommended XML markup language for describing multimedia presentations. Open alternative to Flash and MS ShadowLight ?
tries to extract some information from a HTML semantic rich document. It only uses informations available through a good usage of the semantics defined in HTML.