<script>
    // call() and apply()
    var obj = {
        num: 2
    }

    var addThis = function(a, b, c) {
        console.log(this.num + a + b + c);
    }

    addThis.call(obj, 10, 10, 5); // 27
    addThis.apply(obj, [10, 10, 5]); // 27

</script>