Web Standards and Word Wide Web Consortium W3C

Web standards put into place a common protocol for all web browsers to use and show a web page. The main organization pushing these standards is the World Wide Web Consortium (WC3).

Main Web Standards

Valid code
The principles outlined for the code that makes a web page have been developed to achieve consistency. It's easy to make sure your code at validator.w3.org. Make sure you use the correct DOCTYPE when you try and validate your code.

Semantically Correct Code
In simple terms, semantic web denotes usage of XHLML for content and of CSS for presentation. In particular this means structured organization of h1/h2 etc. tags and only using tables for tabular data, not to layout a web page.

Cascading Style Sheets (CSS)
Cascading Style Sheets (CSS) is a simple method for adding style (e.g. fonts, colors, and spacing) to Web documents. They exist parallel to the (x)html code and so let you semantic code form presentation (CSS).

For more details, please visit http://www.webstandards.org/about/