We've mentioned web standards repeatedly on this site. While you don't really want to know all the ins and out of web coding and technical considerations, it helps to be aware of the essentials. Web standards were developed to bring the web under one universal platform that is accessible to all on any web enabled device. This means it is easier to deliver your message to your customers. It means it takes less time to develop; it is more reliable, more compatible with past and present technologies and it is also cheaper.
To obtain in depth information on web standards, go to the World Wide Web Consortium and read the pages relevant to you.
The actual standards are:
Extensible Hypertext Markup Language (XHTML) 1.0
XHTML 1.1
Extensible Markup Language (XML) 1.0
Cascading Style Sheets (CSS) Level 1
CSS Level 2
CSS Level 3
Document Object Model (DOM) Level 1 (Core)
DOM Level 2
ECMAScript 262 (the standard version of JavaScript)
Additional Presentation Languages (Markup)
Mathematical Markup Language (MathML) 1.01
MathML 2.0
Scalable Vector Graphics (SVG) 1.0
Valid code adheres strictly to the standards listed above and is checked in a validator for errors. You can check your pages here for standards compliance.
Breaking your site into separate elements, that is, one for content and one for style (CSS), has many advantages. The content is available to text only devices. The page downloads faster. It is easier to change the appearance of your site and you have more control of presentation.
Writing semantic code means using code logically for its intended purpose. Many designers create imitations of code elements to force their desired style. This reduces accessibility to mobile, WAP, and other web devices.
In summary, pages that meet the specifications: