function show_unav(item) {
  clear_unav();
  if(document.getElementById("sub_nav"))
    document.getElementById("sub_nav").style.display = "none";
  if(! item)
    return;
  document.getElementById("sub_nav"+item).style.display = "block";
}
		  
function clear_unav() {
  var unav = new Array("1","2","3","4","5");
  for(var i=0;i<unav.length;i++)
  document.getElementById("sub_nav"+unav[i]).style.display = "none";
  if(document.getElementById("sub_nav"))
    document.getElementById("sub_nav").style.display = "block";
}

function MM_findObj(n, d) { //v4.0
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && document.getElementById) x=document.getElementById(n); return x;
}

function MM_validateForm() { //v4.0
  var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
  for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=MM_findObj(args[i]);
    if (val) { nm=val.name; if ((val=val.value)!="") {
      if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
        if (p<1 || p==(val.length-1)) errors+='- '+nm+' - Fehler!!\n';
        if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
          min=test.substring(8,p); max=test.substring(p+1);
          if (val<min || max<val) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
    } } } else if (test.charAt(0) == 'R') errors += '- '+nm+'\n'; }
  } if (errors) alert('Felder bitte ausfuellen:\n'+errors);
  document.MM_returnValue = (errors == '');
}