Pluginweb.Net

Kyle Simpson has announced a new family of opensource projects called flensed and the first project being flXHR which "utilizes javascript+flash to create a complete, literal drop-in replacement (by being API identical) for the native browser XHR (Ajax) communication mechanism. However, flXHR uses Flash Player's security model to enable direct cross-domain communication, and also has a number of other very helpful extensions."

http://flxhr.flensed.com/code/tests/flxhr-4.html

There are a number of demos which illustrate how it easy it is to take the API-compatible flXHR and swap it to any of your favorite JS frameworks (Dojo, Prototype, YUI, ExtJS, etc) in place of its usage of native XHR... once the simple adapt/swap happens, everything else about the framework library communication works the same, because flXHR speaks the same familiar protocol and API, and so it really is what I like to call "set it and forget it" good.

Hasn't this been done before?

There have been several other attempts at similar things before, including SWFHttpRequest, FlashXMLHttpRequest, Fjax, and F4A. However, all those fell short of the mark in different ways. On my site, there are comparison charts and detailed FAQ's which show how flXHR stands up to these predecessors, and exceeds them in very important and powerful ways. I believe flXHR has accomplished its goal, which was to be *the* complete solution for SWF-based Ajax calls as an identical API-compatible drop-in replacement for native XHR, not to mention many helpful improvements including robust error callback handling, timeouts, and convenience configuration functions, to name a few.