FAB – Flex/AJAX Bridge – is a library created by Ely Greenfield, who is a good friend and Flex Architect.
<fab:FABridge xmlns:fab=”bridge.*” />
<mx:Button id=”okButton” label=”OK” />
var flexApp = FABridge.flash.root();
// handle the click event here.
You can read more about it on Ely’s blog, which I predict will be worth reading.