(Right-Click Name and add to Favorites, then put in Favorites Bar)
Name Src Description
ShowCompatInfo
(click to preview) 		ShowCompatInfo.js This bookmarklet check if there's a META tag or server header specifying x-ua-compatible, and also displaying the document mode.
Clear Authentication Cache (See Description) This one just makes a call to document.execCommand('ClearAuthenticationCache');

This bookmarklet also does not create a new SCRIPT block, so is an example of just doing something via the Link URL.

Source: 
javascript:(function(){document.execCommand('ClearAuthenticationCache');})();

Show Cookie (See Description) This bookmarklet simply pops up a dialog showing the value of document.cookie

Source: 
javascript:(function(){alert(document.cookie);})();