js-内置对象

1.创建对象

person=new Object();
person.firstname="John";
person.lastname="Doe";
person.age=50;
person.eyecolor="blue";

或person={firstname:"John",lastname:"Doe",age:50,eyecolor:"blue"};

2.构造函数

function person(firstname,lastname,age,eyecolor){
　　this.firstname=firstname;
　　this.lastname=lastname;
　　this.age=age;
　　this.eyecolor=eyecolor;
　　this.changeName=changeName;
　　function changeName(name){
　　　　this.lastname=name;
　　}
}

myMother=new person("Sally","Rally",48,"green");
myMother.changeName("Doe");

3.for...in 

循环中的代码块将针对每个属性执行一次