Object As Key For Associative Array

Is it possible to have an Object as the key for an Associative array
like in the following example....


function Obj(var1, var2)
{
this.var1 = var1;
this.var1 = var1;


}
function test() {
var sectionArray = new Array();
var obj = new Obj("c","k");
var obj2 = new Obj("3","n");
var obj3 = new Obj("v","qk");

sectionArray[obj] = "king";
sectionArray[obj2] = "queen";
sectionArray[obj3] = "joker";
alert(sectionArray[obj]);
}

This does not give any error but the alert says "joker" instead of
"king". Is there anything wrong with my code or is an Object something
that just can not be used as a key.

If it is the latter can someone please suggest another way for me to do
it? Can I use a concatenated String instead of an object? My only
problem then is how would I extract the values from the String, does
JavaScript have a tokenizer method like Java?