A lot of designers mention valid design, and it sounds great when dropped into conversation:
“nice weather we’re having isn’t it?”
“yes, beautiful”
“talking of beautiful, did you know all my designs are valid”.
Ok, it’s pretty improbable that the conversation would go exactly like that, but it does still beg the question, what does valid design really mean.

Well, generally speaking, when web authors or designers talk about having a valid design, or a valid website,they’re talking about one of two things, and sometimes both things at the same time:

• Cascading Style Sheets (CSS)
• (X)HTML

Let’s take those two items one at a time. First the CSS:

CSS are, basically, what control the “look” or aesthetics of a website.

It used to be that the design of a website was achieved through the complicated use of tables. These tables would be nested together to create a design, and although it worked, it was a cumbersome process which involved a huge amount of coding, was complex even for minor changes to a website’s design, caused large server loads, and basically was never meant to be used that way in the first place.

Enter Cascading Style Sheets. CSS seperated the design elements of a website from the rest of the code, allowing for more streamlined coding, less server load, and seperation of content and aesthetics. Nowadays the only time you should see a designer using tables is for data that needs to be presented in a tabular format.

Blah, blah, blah. What does all this have to do with being valid though? Well, the W3C implements and maintains standards for CSS (currently CSS level II). In order for a website to be valid, it should conform to the standards set out by the W3C. There is, at the moment, a slight controversy with this however. CSS level III is (and has been for a while) in the works, with many advanced features which simply are not possible with CSS level II. The better browsers already have some limited support for some of these features, but they are in proprietary format, and until CSS III becomes the official standard, any website using these proprietary CSS level III features will fail validation. In fact, because of the css rounded corners I use on this very site it will not validate!

Ok, on to the second part, the (x)html. html, and it’s modern day counterpart xhtml, are the building blocks of websites. It’s the code that’s used to tell your browser what goes where, headings, emphasized text, blockquotes,links, etc.

It is important that html, and especially xhtml, is well formed and coded correctly so that browsers interpret it correctly. If a web document is improperly coded things may not appear the way the author intended them to be presented. The best way to think of this is in the same terms as your native language. While it is possible to get by with misspelled words or malformed sentences it is, at some point, going to become a problem. This also holds true with the language of html and xhtml. Again, the validation of html and xhtml are both undertaken by the w3c. In this instance I can safely say this site does pass validation.