JavaScriptでクラス継承

JavaScriptでクラスの継承をするには、

 var car = function(){};
 car.prototype = {
  run:function(){
   alert( "走る" );
  }
 };

 var truck = function(){};
 truck.prototype = new car();
 truck.prototype.carry = function(){
  alert( "運ぶ" );
 };

 var truck1 = new truck();
 truck1.run();
 truck1.carry();

とすればOK