function checkdl() {
   dlbutton = document.getElementById("attrib-20-69");
   if (dlbutton == null) {
       return true; 
   }
   checked = dlbutton.checked; 
   if (checked) {
      document.getElementById("attrib-26").disabled = true;
      document.getElementById("attrib-23-0").disabled = true;
      document.getElementById("attrib-23-0").value= "";
   } else {
      document.getElementById("attrib-26").disabled = false;
      document.getElementById("attrib-23-0").disabled = false;
   } 
   return true;
}