function themechks(prm) {
 var themeend = document.ngmform.geologictheme.length - 1;
// alert("theme.length = " + themeend + ", prm = " + prm);
 if (prm == "sgl") {
   var cnt = 0;
   var allflg = 1;
   while (cnt < themeend) {
     if(document.ngmform.geologictheme[cnt].checked) {
//       alert("cnt = " + cnt);
       cnt = themeend;
       allflg = 0;
     }
     cnt++;
   }
   if(allflg == 1) {
     document.ngmform.geologictheme[themeend].checked = true;
   } else if (allflg == 0) {
     document.ngmform.geologictheme[themeend].checked = false;
   }
 } else if (prm == "all") {
   var cnt = 0;
   if (document.ngmform.geologictheme[themeend].checked) {
     while (cnt < themeend) {
       document.ngmform.geologictheme[cnt].checked = false;
       cnt++;
     }
   } else {
     document.ngmform.geologictheme[themeend].checked = true;
   }
 }
 updateHits();
}