WWW is a common space where users can share information to work together, play, and socialize. But in this period of tremendous growth, the Web needs guidance to realize its full potential. Web standards provide the necessary guidance and help to ensure that everyone has access to the information we are providing, and also make web development faster and more enjoyable.
Standards compliance makes it easier for the people with special needs to utilize the Web to its fullest. Blind people may have their computer read web pages to them. People with poor eyesight may have pages rearranged and magnified for easier reading. And people using hand-held devices can browse the Web just as easily as those using high-end workstations.
HTML 4.0 - HyperText Markup Language
XML 1.0 - Extensible Markup Language
XHTML 1.0, 1.1, and Modularization
CSS - Cascading Style Sheets
DOM 1 - Document Object Model Level 1
HTML/XHTML as a standard
HTML has evolved during its development, and is available in several versions. All of these versions are standards, and you can select one that meets your requirement. Most of the time, the latest version will be the best choice, unless you target a very specific audience, or older, broken browsers. The version you choose defines the elements and attributes you can use.
For example, in HTML 4.01, you will find the list of elements and the list of attributes you are allowed to use in your pages. You can edit your pages manually, a means usually referred to as "hand-coding" or "writing the source".
List of elements:
List of attributes