获得keyCode 兼容IE， FF

$('confirmButton').observe('keydown',function(event){
   event = event || window.event;
   var e = event.keyCode || event.which;
   if(e == 13) $('confirmButton').click();
  });
  $('confirmButton').observe('keyup',function(event){
   event = event || window.event;
   var e = event.keyCode || event.which;
   if(e == 32) $('confirmButton').click();
  });