I found eaxyXDM to be well.. not so easy. Not in actual usage but it felt like too much of magic going around, which made me uncomfortable using it (what if some thing breaks and I'm not able to fix it..). I ended up using much more limited but much easier to understand code at this location: http://www.onlineaspect.com/2010/01/15/backwards-compatible-...

It uses postmessage for newer browsers and hash location trick for older browsers.