// Definition: zweistellige Seitenzahlen oder "zweistellig mit einem angehängter Buchstaben"
// SprungListe: Seitenzahl, nächster Eintrag: Sprungweite
var List1 = new Array("XX","00",10,11,20,"20a",21,22,"22a","22b","22e","22c","22d","22f","22g","22h","22i","22j","22k","22l","22m","22n",23,24,"24u","24k",25,26,27,28,29,30,31,33,34,"34a","34b","34c","34d","34e","34g",37,38,39);
var List2 = new Array(40,41,"41a","41b","41c","41d","41f","41g","41h","41i",42,43,44,45,46,"46a","46b","46c",47,"47a","47b","47c","47d","47e","47f",50,51,52,"52a","52b","52c","52d","52e","52f","52g","52h","52i","52j","52k","52l","52m",53,54,"54a",55,59);
var List3 = new Array(60,69,70,71,72,73,74,79,"79a","79b","79c","79d",80,81,82,83,84,85,86,87,88,89,90,99,"XX");
var List12 = List1.concat(List2);
var Liste  = List12.concat(List3);

var Spruli =new Array(10,2,20,-2,24,3,25,-3,52,14,53,-14);

function ZurVor(Sprung) {
  var Altseite = 0;
  var Neuseite = 0;
  var i = 0;
  framet = eval("parent.text");
  var Name = framet.location.href;
  var Stelle = Name.indexOf(".htm");
  Name = Name.slice(0,Stelle);
  var Lang = Name.length;
  var Altseite = Name.slice(Lang-3,Lang);
  if (isNaN(Altseite.slice(0,1)))
     Altseite = Name.slice(Lang-2,Lang);
  while (i<Spruli.length) {
     if (Spruli[i] != Altseite) i = i + 2;
         else {
               if (Sprung*Spruli[i+1]<0) i = i + 2;
               else {
                    Sprung = Spruli[i+1];
                    i = 1000;
                    }
               }
      }

  i = 0;
  while (i<Liste.length) {
      if(Liste[i] != Altseite) i=i+1;
      else {
          Neuseite = Liste[i+Sprung];
          i = 1000;
          }
      }
  if (Neuseite == "XX") Neuseite = Altseite;

  var Altlinks = Math.floor(parseInt(Altseite)/10);
  var Neulinks = Math.floor(parseInt(Neuseite)/10);
  if (Neulinks <0) Neulinks = 0;
  if (Altlinks != Neulinks) i=chgImg(Neuseite,'');
  else framet.location.href="Text"+Neuseite+".htm";
  }


function chgImg (Seite, Stelle) {
  framet = eval("parent.text");
  framet.location.href="Text"+Seite+".htm"+Stelle;
  }