What’s this extension for?
With this one-button extension, you’ll be able to check at once the markup and style validation of the currently visited URL.
Just visit a webpage and click on it, you’ll be shown a detailed report including errors and warnings and thier explanations in a single page. Easy and handy.
Download it now, free!
If you see this message at the top of the page, saying: To protect your computer, Firefox prevented this site (xhtml-css.com) from installing software on your computer click “Edit Options”, “Allow,” “Close,” and click the install link again.:
The BeValid! extension can be used on any remote web page. It can’t be used for local pages, such as: http://localhost/… http://127.0.0.1… etc.