Here are the five regular expressions that I have found the most useful for day-to-day web programming tasks: matching a username, matching an XHTML/XML tag, matching an XHTML/XML tag with a certain attribute value, matching and parsing an email address, matching an URL
The WDG's reference section offers background information and technical specifications on HTML authoring. Its main purpose is not to provide browser-specific "hacks", or workarounds for browser bugs or limitations, but to give the correct way to do it.
An international consortium where member organizations, a full-time staff, and the public work together to develop Web standards. W3C primarily pursues its mission through the creation of Web standards and guidelines designed to ensure long-term growth fo