what is the difference between these 2 javascript functions? [duplicate]

Question

I want to know what is the difference between insideFn and outsideFn in the follwoing case :

 function Construct()
 {       
   this.insideFn = function(obj){
   ....
   }
 }

 Construct.prototype.outsideFn = function(obj){
      ...
 }

and which one is efficient to use ?

Answer 1

In the first case every instance created with Construct will have its own insideFn, which will waste memory in case you will use more than one instance. In the second case each instance of Construct will have just a reference to outsideFn. So the latter is better.