Today I learned the hard way that our beloved Internet Explorer doesn’t handle HTML5 cross-domain messaging functionality (AKA postMessage) correctly.
I have done a reasonable amount of research before I invested a significant time into this, and so I knew it doesn’t postMessage across tabs and windows beforehand. This limitation was not a problem for me, because I was going to use this in IFRAME.
The problem that I discovered much too late is that IE only accepts a string as a message (see BSTR in a signature? That’s a Windows speak for passing UTF-16 strings.) This is despite the fact that the draft spec allowed any object and not just strings as early as Novemember 2010 .
So I’m posting this here in the hope that this will prevent other people from wasting time.