title: AJAX Autosave functionality
body: <p>What's the best javascript library, or plugin or extension to a library, that has implemented autosaving functionality?</p>
  
  <p>The specific need is to be able to 'save' a data grid. Think gmail and Google Documents' autosave.</p>
  
  <p>I don't want to reinvent the wheel if its already been invented. I'm looking for an existing implementation of the magical autoSave() function.</p>
  
  <p>Auto-Saving:pushing to server code that saves to persistent storage, usually a DB. The server code framework is outside the scope of this question.</p>
  
  <p>Note that I'm not looking for an Ajax library, but a library/framework a level higher: interacts with the form itself.</p>
  
  <p>daemach introduced an implementation on top of jQuery @ <a href="http://daemach.blogspot.de/2007/03/autosave-jquery-plugin.html" rel="noreferrer">http://daemach.blogspot.de/2007/03/autosave-jquery-plugin.html</a> [script host down]. I'm not convinced it meets the lightweight and well engineered criteria though.</p>
  
  <p><strong>Criteria</strong></p>
  
  <ul>
  <li>stable, lightweight, well engineered</li>
  <li>saves onChange and/or onBlur</li>
  <li>saves no more frequently then a given number of milliseconds</li>
  <li>handles multiple updates happening at the same time</li>
  <li>doesn't save if no change has occurred since last save</li>
  <li>saves to different urls per input class</li>
  </ul>