We have built a comprehensive, browser-based Online Code Editor using the SourceForge CodeMirror project.
Here is the editor in Blackboard Theme, editing a Clojure source file, with a selected area.
Preview Mode - preview your changes using an optional Unified Diff Preview, then Confirm, Keep Editing or Discard changes.
Mixed editing of tag-based and brace-based languages. The example below shows a JSP file with HTML with embedded Java code.
Our system supports UTF-8 all the way through, so you can edit files in any language you can read in your browser
Save-As feature with path-support to save as a different folder, anywhere in your private filesystem.
If you accidentally navigate away from a page (eg: BackSpace or by clicking a link), the editor will let you know.
Sign up to try it out!