There is a group called the World Wide Web Consortium (http://www.w3.org) that has played a major role in establishing standards for Web Development. As they describe themselves, "The World Wide Web Consortium (W3C) develops interoperable technologies (specifications, guidelines, software, and tools) to lead the Web to its full potential. W3C is a forum for information, commerce, communication, and collective understanding".
Commonly when people talk of web standards for HTML they will refer to it as XHTML standards. They are one in the same. XHTML is the standard for both HTML and also XML [Note: XML is Extensible Markup Language but we will not be covering that in this course]. XHTML stands for Extensible Markup Hypertext Language. Previous to this there was a standard specifically for HTML that was called HTML 4.0 but that has since been replaced with the XHTML 1.0 standard.
These standards include things like:
- documents must be well-formed: they must have closing tags and must nest properly
- element and attribute names must be in lower case
- attribute values must always be quoted
To see a complete list of the current standards go to http://www.w3.org/MarkUp/
But lets say you are like me and looked at the standards but only understood about half of what was being said. In that case you may want to try using a code validator that tells you were you are on the mark and where you are not. Then you just have to worry about that stuff that didn't "pass". There are a number of free code validators out there including at:
For HTML/XHTML validation you can check:
For CSS validation you can check: