Online source code editing element
I'm wondering if there is some sort of element (preferably jQuery since this library is used) which enables online editing in a (converted) textarea. Basically what I'm looking for is a framework for textarea tabbing and syntaxhighlighting for basic online source-code editing that I can embed in my site. Any suggestions? My Google attempts result in RTE-editors having a 'show code' button which is not what I'm looking for, obvious.
CodeMirror is the serious alternative to ACE. It's used by various projects, including jsFiddle (mentioned in another answer), jsbin and Google Code.