Talking about Several Common Definition Methods of JS Class

//Method 1 Object Direct Quantity

var obj1 = {
 v1 : "",
 get_v1 : function() {
  return this.v1;
 },
 set_v1 : function(v) {
  this.v1 = v;
 }
};

//Method 2 defines a function object

var Obj = function() {
 var v1 = "";
 this.get_v1 = function() {
  return this.v1;
 };
 this.set_v1 = function(v) {
  this.v1 = v;
 }
};

//Method 3 Prototype Inheritance

var Obj3 = new Function();
Obj3.prototype = {
 v1 : "",
 get_v1 : function() {
  return this.v1;
 },
 set_v1 : function(v) {
  this.v1 = v;
 }
};

//Method 4 Factory Mode

function loadObj() {
 var tmp = new Object();
 tmp.v1 = "";
 tmp.get_v1 = function() {
  return tmp.v1;
 };
 tmp.set_v1 = function(v) {
  tmp.v1 = v;
 };
 return tmp;
}

obj1.set_v1('hello1');
alert(obj1.get_v1());

var obj2 = new Obj();
obj2.set_v1('hello2');
alert(obj2.get_v1());

var obj3 = new Obj();
obj3.set_v1('hello3');
alert(obj3.get_v1());

var obj4 = loadObj();
obj4.set_v1('hello4');
alert(obj4.get_v1());

alert(obj1);
alert(obj2);
alert(obj3);
alert(obj4);