(Living wrote)  (Spanish version of this post)

I have received a bulletin from Softonic.com advertising a freeware program that seemed interesting.  It is a toolbar for Explorer that allows you to validate the web page that you are visiting (HTML, css, links) and check its level of accessibility and legibility.
 
It can also show the web page without images, the colors that are being used, the whole page structure, deprecated tags, and it highlights the different elements from the page (any html tag)...

Download the Web Accessibility Toolbar

I hope it works for you ;)