Official W3C specifications for HTML.

Official W3C specifications for CSS2.

The official website for PHP with documentation, FAQ's, bug reporting and more.

HTML, JavaScript, the Document Object Model, and more.

Great resources for all kinds of programming.

Great resources for C++, C#, and general programming.

More great resources for C++, C#, and more.

Documentation of JavaScript from the organization that invented it.

Many resources for VR programming on the web including a great VRML tutorial, library, and node reference.

A fantastic little resource for any java programmer concerned with graphics.

Details on many graphic and audio file formats.

Details on many file formats and other sundry technical formats.

Some resources for assembly language. Especially good for OS developers.

A few different versions of Rawrite and similar programs. Great for anybody playing with their boot sector.

A must-have for anyone who plans to use interrupts. One of the most important resources available free to the assembly programmer.