Why does ExternalInterface breaks when I pass parameter with JSON like string?

Question

I have a very odd problem with Flash 10 and ExternalInterface. I am currently using a homemade bridge to use RTMFP with Javascript and whenever I try to pass data that contains

Answer 1

Admittedly this wouldn't work directly for output to the console in Firebug, but for most other applications (i.e. sending a potentially 'invalid' string to Javascript), escape and unescape should work just fine:

AS3:

var testString:String = "\"\\\"\"";
ExternalInterface.call("showString", escape(testString));

And then in Javascript:

function showString(msg) {
    console.log(unescape(msg));
    document.getElementById('messagebox').innerHTML = unescape(msg);
}