HTML Tidy running as a Chrome extension.
HTML Tidy is a popular utility for checking HTML documents for common mistakes.
It can also present an improved version of the markup, and help make older pages standards compliant.
This browser extension makes it extremely easy to check the currently open page for errors. Use it to double check your own sites or be a hero to someone else.
* Easy to use: Simply click the drop-down icon to view what Tidy finds and suggests.
* Fast: HTML Tidy is built into the extension and runs at the speed of your computer.
* Self contained: HTML is checked locally, and doesn't go through an online HTML validation service.
* Compare HTML: Displays the page source and the HTML suggested by HTML Tidy. A third view highlights any differences between the two.
* Checks the final output: If your pages use server-side scripting, this extension can help test HTML as the browser sees it.
The excellent HTML Tidy utility was written by Dave Raggett and it's currently maintained by a quorum of developers.