Hide Fields in SharePoint Form

<script language="javascript" type="text/javascript">
_spBodyOnLoadFunctionNames.push("hideFields");
function findacontrol(FieldName) {
   var arr = document.getElementsByTagName("!");
   // get all comments
   for (var i=0;i < arr.length; i++ )
   {
      // now match the field name
      if (arr[i].innerHTML.indexOf(FieldName) > 0)
      {         return arr[i];      }
   }
}
function hideFields() {
   var control = findacontrol("Closed");
   control.parentNode.parentNode.style.display="none";
}
</script>