I guess this trick is pretty old, but it’s new to me. It lets you change the text on any Web page. Just activate the page, clear the address bar, and paste this Javascript code into the address bar:

javascript:document.body.contentEditable=’true’; document.designMode=’on’; void 0

Then you can insert text, change text, delete text, and so on. But, obviously, you can’t save your changes back to the server. You can, however, save a local copy. It seems to work much better in Firefox than in IE. I haven’t tried any other browsers.

From j-walkblog.com