How to inherit an Object in JavaScript

 We can use the prototype chain to implement the inheritance of methods from a super class.

1. The method most people use:

   function inherit(sub, supper){
       var subProto = sub.prototype = new supper();
       subProto.constructor = sub;
   }

   Note: this will always call the supper's constructor and it is just a waste in some way.
    
   
2. The method not really inheritance:

   function inherit(sub, supper){
       var subProto = sub.prototype, supProto = supper.prototype;
       for(var i in supProto){
           if(!subProtp[i]) subProto[i] = supProto[i];
       }
   }

   Note: the result of new Sub() instanceof Supper is false. 
3. The method derives from method 1:

   function inherit(sub, supper){
       var subProto = sub.prototype;
       subProto = Object.create(supper.prototype);
       subProto.constructor = sub;
   }
   function inherit(sub, supper){
       var subProto = sub.prototype;
       var F = function(){};
       F.prototype = supper.prototype;    
       subProto = new F();
       subProto.constructor = sub;
   }

   
   
4. The method simplest but IE doesn't support:

   function inherit(sub, supper){
       sub.prototype.__proto__ = supper.prototype;
   }