/**
 * a?￣a?-a?1a??a?§a??a?‰a??a??a?-a??a?≪a?aa??a??a??a‡|c?†
 * rollover2.js
 * Copyright (c) 2007 KAZUMiX
 * http://d.hatena.ne.jp/KAZUMiX/20071017/rollover2
 * 
 * Licensed under the MIT License:
 * http://www.opensource.org/licenses/mit-license.php
 * 
 * a?´a?°a±\a-´
 * 2009/06/02 a??a?ca?|a?¶a?Ra??a?≫a??a??a?§a??a?§a??a?‰c?¶a…?a??aR?a?￡a?|a??a??a ´a??a?≪a￣?a‡|
 * 2007/10/17 a…￢e??
 */

(function(){
   // a??a??a?，e?・c§≫a??a?≪e??a??a?≪a??a??c”¨
   var rolloverImages = [];
   
   function setRollOver2(){
     if(!document.images){return;}
     var imgs = document.images;
     var insert = [];
     for(var i=0,len=imgs.length; i<len; i++){
       var splitname = imgs[i].src.split('_rollout.');
       if(splitname[1]){
         var rolloverImg = document.createElement('img');
         rolloverImages.push(rolloverImg);
         rolloverImg.src = splitname[0]+'_rollover.'+splitname[1];
         var alpha = 0;
         rolloverImg.currentAlpha = alpha;
         rolloverImg.style.opacity = alpha/100;
         rolloverImg.style.filter = 'alpha(opacity='+alpha+')';
         rolloverImg.style.position = 'absolute';

         //a?-a??a?≪a?aa??a??a??a?≫a?￠a?|a??a‡|c?†a??a??a??a??a?’e¨-aR?
         addEvent(rolloverImg,'mouseover',function(){setFader(this,100);});
         addEvent(rolloverImg,'mouseout',function(){setFader(this,0);});

         // a??a?§e??a? a??a??a??a??a?≪e??a? a ´a‰?a?¨a…±a?≪a??a-?a??a?|a??a??
         // a?“a?Ra??c?1a?§e??a? a??a??a?¨document.imagesa??a?，a??a??a??a?￡a?|a，?e??a??
         insert[insert.length] = {position:imgs[i],element:rolloverImg};
       }
     }
     // a†‘a?§a??a?￡a??a?-a??a?≪a?aa??a??a??c”≫a??a?’e??a? 
     for(i=0,len=insert.length; i<len ;i++){
       var parent = insert[i].position.parentNode;
       parent.insertBefore(insert[i].element,insert[i].position);
     }

     // a??a??a?，e?・c§≫a??a?≪a?￣a??a?§a??a?‰c?¶a…?a?’a?￣a?aa?￠a??a??
     addEvent(window,'beforeunload', clearRollover);
   }

   // a?‡aR?e|?c´ a?’a?‡aR?e??a??ao|a?≪a??a??a??a??a?Ra??a?§a??a?‰a?￠a??a?!a?’e¨-aR?a??a??e?￠a?°

   function setFader(targetObj,targetAlpha){
     targetObj.targetAlpha = targetAlpha;
     if(targetObj.currentAlpha==undefined){
       targetObj.currentAlpha = 100;
     }
     if(targetObj.currentAlpha==targetObj.targetAlpha){
       return;
     }
     if(!targetObj.fading){
       if(!targetObj.fader){
         targetObj.fader = fader;
       }
       targetObj.fading = true;
       targetObj.fader();
     }
   }

   // a?￠a?≪a??a?!a??a?’a??a??a?2a??a??a??a?≪e?‘a?\a?‘a??e?￠a?°
   // a??a??a?2a??a??a??a?≪a?aa?￡a??a?‰cμ?ao†

   function fader(){
     this.currentAlpha += (this.targetAlpha - this.currentAlpha)*0.2;
     if(Math.abs(this.currentAlpha-this.targetAlpha)<1){
       this.currentAlpha = this.targetAlpha;
       this.fading = false;
     }
     var alpha = parseInt(this.currentAlpha);
     this.style.opacity = alpha/100;
     this.style.filter = 'alpha(opacity='+alpha+')';
     if(this.fading){
       var scope = this;
       setTimeout(function(){fader.apply(scope)},30);
     }
   }
   
   // a??a?1a?|a?Ra?-a??a?≪a?aa??a??a??c”≫a??a?’a?’e??a??a?≪a??a??e?￠a?°i??e?・c§≫a??c”¨i?‰

   function clearRollover(){
     for(var i=0,len=rolloverImages.length; i<len; i++){
       var image = rolloverImages[i];
       image.style.opacity = 0;
       image.style.filter = 'alpha(opacity=0)';
     }
   }

   // a??a??a?3a??a?’e??a? a??a??e?￠a?°

   function addEvent(eventTarget, eventName, func){
     if(eventTarget.addEventListener){
       // a?￠a??a?3a??a?ca?|a?¶
       eventTarget.addEventListener(eventName, func, false);
     }else if(window.attachEvent){
       // IE
       eventTarget.attachEvent('on'+eventName, function(){func.apply(eventTarget);});
     }
   }

   addEvent(window,'load',setRollOver2);

 })();