不同函数的调用方法

function Person(name,age,job){

      this.name = name;

     this.age = age;

      this.job = job;

      this.sayName = function(){

    alert(this.name);

}

}

1、当作构造函数使用

var person = new Person("zhangsan",28,"teacher");

person.sayName();  //zhangsan

2、作为普通函数调用

Person("lisi",32,"doctor");   //添加到window

window.sayName();

3、在另一个对象的作用域中调用

var o = new Object();

Person.call(o,"wangwu",21,"Nurse");

o.sayName();