Javascript custom type, attribute, method example code summary

Javascript commonly used custom types, attributes, and methods are organized. Friends in need can refer to it.

1. Define the type

function UserObject(parameter) { 
}

parameter can be omitted, which is equivalent to the constructor parameter in C#.
2. Instantiate the custom type

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

3. Add attributes

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

//Use

<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. Add method (circle class)

//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 
}

Associate to custom type:

<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>

Use custom method:

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

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