function hideDwSects(appname) {
 for(os=1;;os++) {
  var haveone = 0;
  for(bt=1;;bt++) {
   var sect = document.getElementById(appname+os+bt);
   if(sect==null || typeof(sect)=='undefined')break;
   sect.style.display='none';
   haveone = 1;
  }
  if(!haveone)break;
 }
}

function dwSelect(dd) {
 var appname = dd.name;
 
 if(dd.id==dd.name+'bits') {
  var ossel = document.getElementById(appname+'os');
  if(ossel==null || typeof(ossel)=='undefined')return;
  var sect = document.getElementById(appname+ossel.value+dd.value);
  if(sect==null || typeof(sect)=='undefined')return false;
 } else {
  var bitsel = document.getElementById(appname+'bits');
  if(bitsel==null || typeof(bitsel)=='undefined')return;
  var sect = document.getElementById(appname+dd.value+bitsel.value);
  if(sect==null || typeof(sect)=='undefined')return;
 }
 hideDwSects(appname);
 sect.style.display='block';
}

function showExpl(lnk) {
 var expl = document.getElementById(lnk.name+'ex');
 if(expl==null || typeof(expl)=='undefined')return;
 lnk.style.display='none';
 expl.style.display='block';
}