var imgDir = "/_images/blog/_8a9/t_hasse/";
  var imgObj = "imgFrame";
  var imgNo  = "imgNo";

  function changeImg(key, imgArray, idxArray, idx1, idx2) {

    var idx = idxArray[idx1];

    if (idx2 == -1) {
      if (idx != 0) {
        idx = idx - 1;
      } else {
        idx = imgArray[idx1].length - 1;
      }
    }

    if (idx2 == 1) {
      if (idx != imgArray[idx1].length - 1) {
        idx = idx + 1;
      } else {
        idx = 0;
      }
    }

    if (idx != idxArray[idx1]) {
      idxArray[idx1] = idx;
      var nameIdx = String(idx1 + 1);
      var objName = imgObj + "_" + key + "_" + nameIdx;
      var noName  = imgNo  + "_" + key + "_" + nameIdx;

      var img = document.getElementById(objName);
      img.src = imgDir + imgArray[idx1][idx];

      var no  = document.getElementById(noName);
      no.innerHTML = idx + 1;
    }
  }