Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation (that is, the look and formatting) of a document written in a markup language. However, it is not simple to create your own CSS. With SelectorGadget it is fairly simple.

SelectorGadget is an open source bookmarklet that makes CSS selector generation and discovery on complicated sites a breeze. To start, just drag the bookmarklet to your bookmark bar, then go to any web page and press it. A box will open in the bottom right of the website. Click on a page element that you would like your selector to match (it will turn green).

SelectorGadget will then generate a minimal CSS selector for that element, and will highlight (yellow) everything that is matched by the selector. Now click on a highlighted element to remove it from the selector (red), or click on an unhighlighted element to add it to the selector.

SelectorGadget has been tested to work in current versions of Firefox and Safari. At the moment it is quite buggy in IE7.