How to construct a new type in Javascript? [duplicate]

You can use following code to create new Class and add methods and properties to that.

function ClassName() {

   //Private Properties
   var var1, var2;

   //Public Properties
   this.public_property = "Var1";

   //Private Method
   var method1 = function() {
      //Code
   };

   //Privileged Method. This can access var1, var2 and also public_property.
   this.public_method1 = function() {
      //Code
   };
}

//Public Property using "prototype"
ClassName.prototype.public_property2 = "Value 2";

//Public Method using "prototype"
//This can access this.public_property and public_property2. 
//But not var1 and var2.
ClassName.prototype.public_method2 = function() {
   //code here
}

//Create new Objects
var obj1 = new ClassName();
//Access properties
obj1.public_property1 = "Value1";

You can also extend exiting Classes.

Check on Crockford's website

Thanks to Glutamat and Felix Kling