startEvent('window','load','LoadEvent') ;

function startEvent(ojNameStr,eventTypeNameStr,funcNameStr){//関数呼び出しの設定
eval(ojNameStr+".on"+eventTypeNameStr+"="+ funcNameStr);
}

function LoadEvent(){//ページ読み込み時の挙動
prImg= new Array();
for (i=0; i<document.images.length; i++){
if(document.images[i].id.indexOf('sw_')>=0){
//preload
baseIMG = document.images[i].src;
newIMG = baseIMG.replace(baseIMG.substr(baseIMG.length-4,4),("_f2" + baseIMG.substr(baseIMG.length-4,4)));
prImg[i] = new Image();
prImg[i].src = newIMG;
startEvent(getLayOjStr(document.images[i].id),'mouseover','Over');
startEvent(getLayOjStr(document.images[i].id),'mouseout','Out');
}
}
}

function getLayOjStr(idName){
if(document.getElementById){
return "document.getElementById('"+idName+"')"
}
}

function Over(){//ロールオーバー時の挙動
IMG = this.id;
baseIMG = document.images[IMG].src;
if(baseIMG.indexOf('_f2')==-1){
newIMG = baseIMG.replace(baseIMG.substr(baseIMG.length-4,4),("_f2" + baseIMG.substr(baseIMG.length-4,4)));
document.images[IMG].src=newIMG;
}
}

function Out(){//ロールアウト時の挙動
IMG = this.id;
baseIMG = document.images[IMG].src;
if(baseIMG.indexOf('_f2')>=0){
newIMG = baseIMG.replace(baseIMG.substr(baseIMG.length-7,7),baseIMG.substr(baseIMG.length-4,4));
document.images[IMG].src=newIMG;
}
}