var walkUrl = new Array(
      "content.html",
      
        'c_villa.html',
        'c_salon.html',
        'c_patio.html',
        'c_schlafraum.html',
        'c_terrasse.html',
        'fuerteventura.html',
        'costacalma.html',
        'playadesotavento.html',
        's_preisliste.php',
        'w_preisliste.php',
        'buchungsanfrage.html',
        'flugverb.html',
        'feedback.html',
        'guestmail.html'
      
    )
    var lastVisited = -1;
    function previous() {
      walk(-1);
    }
    function next() {
      walk(1);
    }
    function walk(offset) {
      var index = indexOfContent();
      index += offset;
      if (index < 0 || index >= walkUrl.length) {
        index = (offset > 0 ? 0 : walkUrl.length - 1);
      }
      parent.content.location.href = walkUrl[index];
      lastVisited = index;
    }
    function indexOfContent() {
      var index = indexOf(parent.content.location.href);
      if (index == -1) index = lastVisited;
      return index;
    }
    function indexOf(url) {
      var index = -1;
      for (i = 0; i < walkUrl.length; i++) {
        if (url.indexOf(walkUrl[i]) != -1) index = i;
      }
      return index;
    }