[melky]

var a = { a:"b" }, b;

b = clone(a);

function clone(o) {
	if(!o || "object" !== typeof o)  {
		return o;
	}
	varc = "function" === typeof o.pop ? [] : {};
	var p, v;
	for(p in o) {
		if(o.hasOwnProperty(p)) {
			v = o[p];
			if(v && "object" === typeof v) {
				c[p] = clone(v);
			}
		else c[p] = v;
		}
	}
	return c;
}

PS взят из интернета.