title: jQuery synchronous non-blocking ajax calls
body: <p>In my web application, I have a series of ajax calls that are fired rapidly. On the server, these need to be processed in the same order as they are sent from the client.</p>
  
  <p>I have been using the <code>async: false</code> configuration in jQuery to do this. However this causes the GUI to become very sluggish while it blocks for calls to finish.  With <code>async: true</code> the GUI is responsive, but the requests are not always processed in order.</p>
  
  <p>Is there an alternative <em>non-blocking</em> way to queue up ajax requests, so the next one is sent only after the previous one has finished?</p>
  
  <p>NOTE:  I don't have a "list" of requests to process. The requests are generated on the fly, so I need to be able to stuff them into some sort of a FIFO queue when they are generated, then consume the queue with some process.</p>