JavaScript Explore--2

Apply and call usages extend the scope of functions on which they are run

<script>        var color = ‘红色‘;        var box = {            color : ‘蓝色‘        }        function sayColor() {            console.log(this.color);        }        sayColor.apply(this);//this指代window作用域        sayColor.apply(box);//box指代box作用域</script>

Note: Apply is the same as call usage, except that the parameters passed are different

<script>    function sum(num1, num2) {        return num1 + num2;    }    function add(num1, num2) {        return sum.apply(this, arguments);//apply传递参数可以用arguments对象代替        return sum.call(this, num1, num2);//call传递参数必须每个都写    }    add(10,10);</script>

JavaScript Explore--2