function smartRollover() {
	if(document.getElementsByTagName) {
		var images = document.getElementsByTagName("img");

		for(var i=0; i < images.length; i++) {
			if(images[i].getAttribute("src").match("_t2hdn2.")) {//画像の最後が「_t2hdn2」の場合
				images[i].onmouseover = function() {
					this.setAttribute("src", this.getAttribute("src").replace("_t2hdn2.", "_a2."));
				}
				images[i].onmouseout = function() {
					this.setAttribute("src", this.getAttribute("src").replace("_a2.", "_t2hdn2."));
				}
			} else if(images[i].getAttribute("src").match("_t2hdn."))	{//画像の最後が「_t2hdn」の場合
				images[i].onmouseover = function() {
					this.setAttribute("src", this.getAttribute("src").replace("_t2hdn.", "_a."));
				}
				images[i].onmouseout = function() {
					this.setAttribute("src", this.getAttribute("src").replace("_a.", "_t2hdn."));
				}
			} 
		}
	}
}

if(window.addEventListener) {
	window.addEventListener("load", smartRollover, false);
}
else if(window.attachEvent) {
	window.attachEvent("onload", smartRollover);
}

if(document.all){ // IE用
	searchCS = document.charset;	
}else{ // IE以外
	searchCS = document.characterSet;
}