the follow piece of code don't work in ie, and I don't know why.

I'm stucked with this. Ie throw a js error. It seems that it can't find the .val() method is not supported;

I tryed with the classic document.getElementById() but I find out the same error.

Someone could help me, please?

1. 　

   <

   script type="text/javascript">

   $

   ("#btn_filtra").click(function(){

   filtro

   =$('#filtro').val();

   tableName

   =$('#tableName').val();
   var url="lista_visualizzazione.php?tableName="+tableName+"&filtro="+filtro;

   $

   ("#lista").load(url);
   });

   $

   ("#btn_add_voce").click(function(){

   alert

   ("add_voce");

   // codice=$('#codice_da_ins').val();

   codice

   =document.getElementById('codice_da_ins').value;

   alert

   (codice);
   //descrizione=$('#descr').val();

   descrizione

   =document.getElementById("descr").value;

   alert

   (descrizione);

   tableName

   =$('#tableName').val();

   alert

   (tableName);
   var url="controller.php?cmd=save&codice="+codice+"&descr="+descrizione+"&tableName="+tableName;

   alert

   (url);

   $

   ("#messaggio").load(url,function(){

   $

   ("#btn_filtra").click();
   });

   });

   })

   　

   </script>