[Decode]

function Test(param1, param2, param3) {
	this.param1 = param1
	this.param2 = param2
	this.param3 = param3 || 4

	this.fn1 = function() {
           console.log(this.param1 + this.param2 + this.param3);
	}

	this.fn2 = function() {
	   console.log(this.param1 * this.param2 * this.param3);
           this.fn1();
	}
}

var a = new Test(1, 2, 3);
a.fn2();