One of the reasons behind Firefox's sustained popularity is the availability of a vast library of extensions. But expanding functionality through these add-ons can have some downsides of their own. For example, most of them are not cross-platform, so if you decide to try another browser your favorite extensions might not be available.

Enter ‘bookmarklets’ -- small applets stored as an URL that are designed to add 1-click functionality to a browser or web page. They are JavaScript-enabled links you can pull into your bookmarks to interact with whatever page you find yourself on. Granted, they might not offer the level of functionality some of the more advanced browser extensions do, but they certainly come in handy and can sometimes be as simple as a single line of code.

From a simple “mail page to” script to a spelling checker to an HTML debugger, all you need to do to enable them is drag a link to your favorites – typically you bookmarks toolbar – and that’s that.