function pmSelectAll() {
           var cbs = document.getElementsByTagName('input');
           for (var i=0; i<cbs.length; i++) {
              if (cbs[i].name.substring(0,11)=='selected_pm') {
                 if (cbs[i].checked) {
                    cbs[i].checked = false;
                 } else {
                    cbs[i].checked = true;
                 }
              }
           }
        }