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();