Colorize CheckSite is a tool that can be used to find potential problems in HTML and CSS. When making websites, you need to keep an eye on two types of standards: the official web standards, which are checked by the W3C Validator, and the unofficial standard of making sure that your website actually works as intended on all commonly used browsers.
The advantage of using CheckSite is that it checks both, and that it does it automatically for all pages within your website. When done, CheckSite will produce an overview of all potential issues found in all pages, including an easy-to-read summary.