var obj = null;
 var tar = null;
 /*If neither source (obj) nor target (tar) exist then fadeOut the div*/
 function checkHover(){
         if(!(obj) && !(tar)){
           $('.nav_prod_drop').fadeOut();
         }  //if
       }// checkHover

    $(document).ready(function(){
       $('.nav_prod').hover(function(){
          $('.nav_prod_drop').fadeIn();
          obj = $(this);
       }, function(){
          obj = null;
         $('.nav_prod_drop').hover(function(){
           tar = $(this);
         },function(){
           tar= null;
           setTimeout("checkHover()", 400);
         });
         setTimeout("checkHover()", 400);
       });
    });