Bookmarklets (or favelets) are bookmarks for your browser that, when clicked, rather than loading a favourite website – run JavaScript to modify the page you are viewing.

CSS debug bookmarklet

An adaptation of a neat CSS debugging tool created by Patrick Brosset

Keyboard = Leopard Bookmarklet

XKCD inspired frivolity.

Tidy URL Bookmarklet

Strips Google Analytics Tracking parameters from the URL of the currently viewed web page. Uses history.replaceState if available to avoid the need for a page reload.

Video still bookmarklet

Grabs a still from the first video element in the page, inserting it as an image in a new window.