Pointers/examples of Chrome Extension/Javascript Code to fetch HTML/Content of tabs

New to Javascript/Chrome extensions.

I’m looking to create a test extension that would capture the HTML/Content of the tabs for the Browser. It would be cool if the test could filter off the “URL” as well.

I’ve been looking over different test apps, and I’ve managed to get the Cookies, but can’t see how to get the content.

I’ve looked over the Chrome/Mozilla stores with no luck.

Pointers are appreciated.

thanks