function zChange() {
   dlz = document.hled.zeme;
   dll = document.hled.lokalita;
   v = dlz.options[dlz.selectedIndex].value;
   if (v!=0) a = eval ("z"+v); else a = new Array ();
   l = a.length/2;
   while (l<dll.options.length) dll.options[(dll.options.length-1)]=null;
   dll.options[0]=new Option('- nerozhoduje -',-1,(sel==0),(sel==0));
   for (i=0; i<l; i++) {
     x = i*2;
     dll.options[i+1]=new Option (a[x+1],a[x],(a[x]==sel),(a[x]==sel));
   }
}