It has been said that the Internet is one of the most difficult design environments to work in. Depending on the browser, operating system, platform (Apple vs. PC) or device (PDA or iPhone) someone is using, they are likely to have a different experience when visiting your website. Layout, fonts and colours could all display differently on different devices.

Validating your website design is an excellent way to ensure that your site will perform well across most of these (barring older browsers like Internet Explorer 6). Validation ensures that the appropriate web standards are met (for more on web standards you can check out this post).

Ways to validate your design

There are two ways to perform a web validation test. You can either enter your URL on the W3C site or use the Firefox add-on web developer toolbar, to automatically send the URL to the validation site.

Faster loading times

Another reason for adhering to these standards is that they lead to faster loading times and make it easier to maintain your site as they require that you separate the HTML and CSS files.

Errors

Don't despair if your site has a lot of errors initially. Often fixing just one error has a knock on effect and does away with a lot of the others. The W3C provides good explanations below each error allowing for easy fixing and for you to achieve validation status. It is important to remember that, over time and through updates to the site, more errors can creep in, so validate your site regularly.

Doctype

Also check that you are using the right Doctype (at the top of your HTML) as the validator checks the site against this. For example, I recently switched to Strict Doctype and I still get errors for using td width="" which would pass validation if I specified Transitional in the Doctype.

Website validation, while it can be a pain in the butt, is the only real way to make sure your website displays the way it is supposed to.