js 定义函数的几种方法 以及如何调用

/*1.方法调用模式：
    先定义一个对象，然后在对象的属性中定义方法，通过myobject.property来执行方法，this即指当前的myobject
    对象。*/
        var car = {
            carId:123,
            carName:"奥迪",
            carColor:"red",
            say:function(){
                console.log(this.carName+" color is "+this.carColor);
            }
        };
        car.say();

    /*2.函数调用模式
    定义一个函数，设置一个变量名保存函数，这时this指向到window对象。*/
        var mycar = function(name,color){
        　　return "my car is " +color+" and "+name ;
        }
        console.log(mycar("奥迪","红色"));

    /*3.构造器调用模式
    定义一个函数对象，在对象中定义属性，在其原型对象中定义方法。在使用prototype的方法时，必须实例化该对象才能调用其方法。*/
        var yourcar = function(name,color){
            this.name = name;
            this.color = color;
        };
        yourcar.prototype ={
            say:function(){
                console.log("your car is " +this.name + " and " +this.color);
            }
        };
        var yourcar = new yourcar("奔驰","蓝色");
        yourcar.say();

    /*4.apply,call调用模式*/
        function count(num1, num2) {
            return num1 + num2;
        }
        console.log(count.call(window, 10, 10)); //20
        console.log(count.apply(window,[10,20])); //30

        window.a=100;
        window.b=300;
        var myobject={a:40,b:50};
        var sum = function(){
        　　return this.a+this.b;
        };
        var sum1 = sum.call(window);
        // var sum2 = sum.call(myobject);
        var sum2 = sum.apply(myobject);
        console.log(sum1+"========="+sum2);

        // 发现apply()和call()的真正用武之地是能够扩充函数赖以运行的作用域，如果我们想用传统的方法实现
        window.a=100;
        window.b=300;
        var myobject={a:40,b:50};
        function sum(){
            console.log(this.a+this.b);
        }
        console.log(sum());
        myobject.sumnumber = sum;
        console.log(myobject.sumnumber());

        window.color = "red";
        var o = { color: "blue" };
        function sayColor(){
            console.log(this.color);
        }
        sayColor();
        var OSayColor = sayColor.bind(o);
        OSayColor(); //blue