About Application.ExternalCall...I was wondering what happens if I call a java script which returns a value ? I guess Application.ExternalCall discards it ...

you can not get retuned value but you can call a unity function in your javascript by "sendmessage" and you can send one argument with sendmessage function. you can use this capability to guide your game from your javascript. first you use externalcall to call your javascript function and then after calculations when you want to return the value you will use sendmessage with returned value passed as argument to a function defined in your game for a GameObject. for more information see unity and browser communication in manual.

How do I pass two or more parameters, I try

browser javascript:

unity.SendMessage("obj", "FunctionTest", "pr1", "pr2");

uniy3d javascript:

function FunctionTest(p1:String, p2:String) {


it will complain the parameter numbers has some problem!.