/********************************************************
 *
 *  拡張ロールオーバー・オブジェクト
 *
 *  Copyright (c) 2008.12.29 AOK.
 *
 ********************************************************/

function imageRollover(exceptId, canSwap, notLink) {
  var prev = null;

  /* URL のスワップ */
  var swapURL = function(src, over) {
    if (src.match(/\.gif$/)) {
      if (!over && src.match(/\-over\.gif$/))
        return src.replace(/\-over\.gif$/, '.gif');
      else if (over && !src.match(/\-over\.gif$/))
        return src.replace(/\.gif$/, '-over.gif');
    } else if (src.match(/\.jpg$/)) {
      if (!over && src.match(/\-over\.jpg$/))
        return src.replace(/\-over\.jpg$/, '.jpg');
      else if (over && !src.match(/\-over\.jpg$/))
        return src.replace(/\.jpg$/, '-over.jpg');
    }
    return src;
  }

  /* 画像のスワップ */
  var swapImage = function(obj, over) {
    if (obj.tagName != 'IMG') return;
    obj.src = swapURL(obj.src, over);
  }

  /* イベント ハンドラ */
  var doRollover = function(e) {
    var obj = e.srcElement || e.target;
    if (obj != null && obj.tagName == 'A') obj = obj.firstChild;
    if (prev != null) swapImage(prev, false);
    if (obj != null) swapImage(obj, true);
    prev = obj;
  }

  var doRollout = function(e) {
    var obj = e.srcElement || e.target;
    if (obj != null && obj.tagName == 'A') obj = obj.firstChild;
    if (prev != null) swapImage(prev, false);
    if (obj != null) swapImage(obj, false);
    prev = null;
  }

  /* ロールオーバー除外設定 */
  var doSet = function(obj) {
    if (canSwap) {
      var src = obj.src;
      if (src.match(/\.gif$/))
        obj.src = src.replace(/\.gif$/, '-self.gif');
      else if (src.match(/\.jpg$/))
        obj.src = src.replace(/\.jpg$/, '-self.jpg');
    }
    if (notLink) {
      var pobj = obj.parentNode;
      if (pobj != null && pobj.tagName == 'A')
        pobj.removeAttribute('href');
    }
  }

  /* 画像先読み */
  var preLoad = function(obj) {
    var img = new Image();
    img.src = swapURL(obj.src, true);
  }

  /* イベントの登録 */
  this.onloadHandler = function() {
    for (var i = 0; i < document.images.length; i++) {
      var obj = document.images[i];
      if (obj.className == null) continue;
      if (obj.className.match(/\bROLLOVER\b/) == null) continue;
      if (exceptId != null && obj.id == exceptId) { doSet(obj); continue; }
      var pobj = obj.parentNode;
      if (obj.attachEvent) {
        obj.attachEvent('onmouseover', doRollover);
        obj.attachEvent('onmouseout', doRollout);
        if (pobj != null && pobj.tagName == 'A') {
          pobj.attachEvent('onfocus', doRollover);
          pobj.attachEvent('onblur', doRollout);
        }
      } else {
        obj.addEventListener('mouseover', doRollover, false);
        obj.addEventListener('mouseout', doRollout, false);
        if (pobj != null && pobj.tagName == 'A') {
          pobj.addEventListener('focus', doRollover, false);
          pobj.addEventListener('blur', doRollout, false);
        }
      }
      preLoad(obj);
    }
  }

  if (window.attachEvent)
    window.attachEvent('onload', this.onloadHandler);
  else
    window.addEventListener('load', this.onloadHandler, false);
}

/********************************************************

 var IRollover = new imageRollover();
 var IRollover = new imageRollover('page1', true, false);

 ********************************************************/