formhacker boomarklet
The bookmarklet posted here, can be extremely useful when you want to manipulate the appearance of web pages. Drag the formhacker bookmarklet button to the toolbar of your web browser and when it's clicked, no matter what web page you're visiting you'll be able to automatically check off all check boxes; select each radial button; edit any text; or find and replace any terms on the page.
You can also easily display passwords.