This DEMO is using Uploadify (JQuery Pulgin) to AJAX upload. I write some script to return a session & using JS to call back this session for UI display.
See the following link for the DEMO:
http://demo.jarnvid.com/uploadify/uploadify.php
See more about uploadify:
http://www.jarnvid.com/jquery/2-upload-pulgin-uploadify