function selectAllCheckboxes() {
      var checkboxes=document.getElementsByClassName('checkbox');
   for(var i=0; i<checkboxes.length; i++)
      checkboxes[i].checked=$('select_all').checked;
}
function noenter(e) {
   if(window.event) // IE
      key = e.keyCode
   else if(e.which) // Netscape/Firefox/Opera
      key = e.which
   if (key == 13) {
      $('search').focus();
      return false;
   }
   return true;
}