jsFiddle is an  shell editor which allows you ( web designers and web developers ) to write custom JavaScript code to create an environment that is based on the popular Javascript frameworks.

jsFiddle presents an interface that is divided into 4 key parts: HTML editor, CSS editor, JavaScript editor, and the output result

with jsFiddle allows you to choose popular javascript framework & version of your choice (such as Mootools, jQuery, Dojo, Prototype, YUI, Glow, Vanilla). Also, if any, you can add a free framework like Mootools jQuery UI or More. jsFiddle has a great feature is the ability to store and share code generated with unique URL generated. Optional, jsFiddle embedding features also. With features as mentioned earlier, this is an almost perfect platform to try and share the JavaScript code without the need of a website.