Are you web pages ‘valid’? Valid?? What does that mean?
Web pages are typically written using Hypertext Markup Language (HTML) and Cascading Style Sheets (CSS). It’s important that your site uses valid HTML and CSS code so that the search engines can index your site properly.
Like all computer languages, HTML and CSS change constantly. The World Wide Web Consortium (W3C) is the governing body that establishes what is valid HTML/CSS and what is not. Search engines obey the HTML/CSS standard. If there are errors in the HTML/CSS code of your web page, then search engines might not be able to read your web page properly. Accordingly, you may be penalised in the rankings.
To test your site for valid code, visit http://www.w3.org/QA/Tools/
