document.onkeyup = KeyCheck;

function KeyCheck(e)
{
   var KeyID = (window.event) ? event.keyCode : e.keyCode;

   switch(KeyID)
   {
      case 16:
	//document.Form1.KeyName.value = "Shift";
	break;
	case 17:
	//document.Form1.KeyName.value = "Ctrl";
      break;
      case 18:
      //document.Form1.KeyName.value = "Alt";
      break;
      case 19:
      //document.Form1.KeyName.value = "Pause";
      break;
      case 37:
      //document.Form1.KeyName.value = "Arrow Left";
      alert("left");
      break;
      case 38:
      //document.Form1.KeyName.value = "Arrow Up";
      break;
      case 39:
      //document.Form1.KeyName.value = "Arrow Right";
      alert("right");
      break;
      case 40:
      //document.Form1.KeyName.value = "Arrow Down";
      break;
      }
}