JSFiddle is a sort of interactive pastebin site that I’ve been finding useful lately. It features three panes for entering HTML, CSS and JavaScript, and a fourth where the resulting output is rendered. If you save the workspace, it generates a URL like http://jsfiddle.net/fLP64/ and will even save each revision as you update it. You can share the URL to show off the result, and the other user can play with the code as well.
This is great for two scenarios. You can use it to experiment with a bit of CSS or JavaScript for brainstorming purposes, or you can use it if you need to ask someone for help. (It’s a lot easier to figure out what’s going wrong with someone’s code or markup if you can jump right in and start messing with the code.) Chris Coyier (of CSS-Tricks) uses it all the time to show off CSS experiments that will likely be used in future posts of his.
