core_js_20.js

var Parent = function() {
     this.print= function() {
          alert("Parent, this.print");
     };
};

var Children = function() {
     /*
      this.print=function() {
           alert("Children, this.print");
      };
      */
};

Object.prototype.print= function() {
     alert("Object.prototype.print");
};

Parent.prototype.print= function() {
     alert("Parent.prototype.print");
};

/*
 Children.prototype.print=function() {
      alert("Children.prototype.print");
 };
 */

Children.prototype = new Parent; 

var children = new Children();
children.print();