function toggletr(onOff){
  var tbl = document.getElementById("courseTbl");
  var row = tbl.rows[0];
  var cell = row.cells[2].innerHTML;
//  alert(row.getAttribute("id"));
  var vStyle = "";
  var sDate = "";
  var hs = "show";
  for(var i=0;i<=tbl.rows.length;i++){
    vStyle = "";
    row = tbl.rows[i];
    hs = (row.getAttribute("id")).substring(0,4);
    if(onOff == "off" && hs == "hide"){
      vStyle="none";
    }
    else{
      vStyle="";
    }
    row.style.display = vStyle;
  } 
}