function Bobj(img_obj,img_path){
		       //se crean las propiedades
			   this.objs = new Array(new Image(),new Image());
			   this.objs[0].src = img_path + ".gif";
			   this.objs[1].src = img_path + "_on.gif";
			   
			   var _objs = this.objs;
			  
			   img_obj.onmouseover = function(){img_obj.src = _objs[1].src;};
			   img_obj.onmouseout =  function(){img_obj.src = _objs[0].src};
		}