JavaScript Quiz #5

This quiz covers some of the JavaScript operators in order to explain they can work together inside expressions. Assume that we have the following JavaScript code:

var object1 = {
    valueOf: function () {
	return 10;
    },
    toString: function () {
	return "object1";
    }
};

var object2 = {
    valueOf: function () {
	return 20;
    },
    toString: function () {
	return "object2";
    }
};

var object3 = {
    valueOf: function () {
	return 30;
    },
    toString: function () {
	return "object3";
    }
};

var result = (object2, object1, object3) + object1 +-- object1; 
alert(result);

What is the output of the alert?

Read the complete answer