function lockout (boxname,fieldname) {
  boxobj = eval("document.theForm." + boxname);
  fieldobj = eval("document.theForm." + fieldname);
  
  if (boxobj.checked == true) {
     fieldobj.value="0"; 
     fieldobj.readOnly=true; 
  } 
  else { 
    fieldobj.readOnly=false; 
  } 
}