1. 定义类型

function UserObject(parameter) { 
}

parameter 可省略，相当于C#中构造函数参数。
2. 实例化自定义类型

<script type="text/javascript"> 
function userobject(parameter){ 
} 
//myobject is now an object of type userobject! 
var myobject=new userobject("hi") 
alert(myobject) 
</script>

3. 添加属性

function userobject(parameter){ 
this.firstproperty=parameter 
this.secondproperty="This is the second property" 
}

//使用

<script> 
var myobject=new userobject("hi there.") 
//alerts "hi there." 
alert(myobject.firstproperty) 
//writes "This is the second property" 
document.write(myobject.secondproperty) 
</script>

4.添加方法 （circle类）

//first method function 
function computearea(){ 
var area=this.radius*this.radius*3.14 
return area 
} 
//second method function 
function computediameter(){ 
var diameter=this.radius*2 
return diameter 
}

关联到自定义类型：

<script type="text/javascript"> 
/*the below creates a new object, and gives it the two methods defined earlier*/ 
function circle(r){ 
//property that stores the radius 
this.radius=r 
this.area=computearea 
this.diameter=computediameter 
} 
</script>

使用自定义方法：

<script type="text/javascript"> 
var mycircle=new circle(20) 
//alerts 1256 
alert("area="+mycircle.area()) 
//alerts 400 
alert("diameter="+mycircle.diameter()) 
</script>