title: Is there a decent browser-based javascript self-editor?
body: <p>Is there a decent browser-based javascript self-editor?</p>
  
  <p>It is obvious one can make a quick js editor with a page containing a form textarea, some buttons and callbacks.  I'm wondering if someone has taken that as a beginning and ran with it.</p>
  
  <p>The javascript to be edited could be defined in a global string or it could be a served .js </p>
  
  <p>The ideal editor would show a pretty version inside a browser window and provide some kind of development environment for editing the script.  </p>
  
  <p>It is understood that user-written scripts would only exist inside the browser and could not be saved without some additional server-side functionality.  The ideal package would discuss and explore this.... but I'd settle for anything that just lets the user make their own simple changes to 100-200 line scripts. </p>