function SelectChk(form_name, chk)
{
  var oForm = document.forms[form_name];
  for (var i = 0; i < oForm.elements.length; i++)
  {
     var oEl = oForm.elements[i];
     if (oEl.type == 'checkbox')
     {
       oEl.checked = chk;
     }
  }
}

function SelectElement(form_name, num)
{
  var oForm = document.forms[form_name];
  var x = 0;
  for (var i=0; i < oForm.elements.length; i++)
  {
    var oEl = oForm.elements[i];
    if (oEl.type == 'checkbox')
    {
      if (x == num)
      {
        oEl.checked = !oEl.checked;
        break;
      }
      x++;
    }
  }
}