Building a website is a complicated process, and testing your finished product
on every possible browser can be even more daunting. However, because modern
browsers such as Safari, Mozilla, and Internet Explorer 6 are compliant with the
World Wide Web Consortiums W3C standards, testing your pages with the W3C
Validation Tool is a great way to ensure that your pages work with modern
browsers. The W3C Validator provides a line-by-line level of feedback, such as
error information with references to the standards, on any URL you submit or
HTML file you upload.