js 构造函数

function  Person(name,age,job){
    this.name=name;
    this.age=age;
    this.job=job;
    this.sayName=function(){
      alert(this.name);
    }
}
var person1=new Person("Lucy",22,"nurse")

//当做构造函数使用
var person=new Person("Lucy",22,"nurse");
person.sayName();  //Lucy 

//作为普通函数调用
 Person("Lucy",22,"nurse");  //添加到window
window。sayName();  //Lucy

//在另一个对象的作用域中调用
var o=new Object();
Person.call(o,"Lucy",22,"nurse");
o.sayName():  //Lucy