Neko is also worth a look, it is another solution from Nicolas ( haxe's creator ) and can easily be targeted from haxe, it is often a more robust solution than PHP in the form of Neko vm, the concept of targetting PHP and then remapping to Neko, when traffic increases is really powerful.
http://nekovm.org/
Spod ( ORM mapping ) is being unified between backend targets, allowing Haxe3 to work easily with databases in an OOP structured approach, while still allowing the same code base to compile to Neko and PHP solutions.
http://haxe.org/doc/neko/spod
Haxe remoting allows objects to transfer between targets, so from flash, to Javascript or to PHP/Neko/Nodejs.
http://haxe.org/doc/remoting
There are many other examples of haxe/haxe related workflows that make the haxe eco system worth exploring, my thoughts are that you probably won't want to work directly in any other language after using Haxe, I certainly resent clients that want me to use as3 and the thought of raw js is enough to send one to an early grave. Really worth using haxe a pragmatic practical choice for rapid lite developement.