javaScript this

function user(name,age){

this.name=name;

this.age=age;

this.say= say;

}

function say(){

alert("age= "+age+"name= "+name);

}

var user1 = new user();

user1.age=12;
user1.name='s'

var user2 = new user();

user2.age=23;
user2.name='kll';


user1.say();

user2.say();