The W3C's CSS and HTML Validators
The W3C (World Wide Web Consortium) hosts online CSS and HTML validators that you can use to validate your CSS style sheets and HTML files.
Using the W3C CSS Validator
To use the W3C CSS Validator, just go to the W3C's home page at http://www.w3.org/ and click the CSS Validator link in the sidebar menu. You can also access the W3C CSS Validator directly at http://jigsaw.w3.org/css-validator/ (see Figure 15.1).
Figure 15.1. You can use the W3C's CSS Validator to check the validity of your CSS style sheets.
As you'll notice in Figure 15.1, you can also download the W3C's CSS Validator and run it from your own local ...