function smartOver() {

	smartRollover('menu');	//ロールオーバーを適用させたい箇所のIDを指定

//	smartRollover('menu2');

}

function smartRollover(idName) {

	if(document.getElementsByTagName) {

		var images = document.getElementById(idName).getElementsByTagName("img");

		for(var i=0; i < images.length; i++) {



			if(images[i].getAttribute("src").match(/_off\./))

			{

			fileName = new Array(images[i].getAttribute("src").replace("_off.", "_on."));

			preImages = new Array();

			for (j=0; j<fileName.length; j++)

			{

				preImages[j] = new Image();

				preImages[j].src = fileName[j];		//「_on」の画像をプリロード

			}



				images[i].onmouseover = function() {

					this.setAttribute("src", this.getAttribute("src").replace("_off.", "_on."));	//マウスオーバーで_off→_on

				}

				images[i].onmouseout = function() {

					this.setAttribute("src", this.getAttribute("src").replace("_on.", "_off."));	//マウスが離れたら_on→_off

				}

			}

		}

	}

}

if(window.addEventListener) {

	window.addEventListener("load", smartOver, false);	//実行

}

else if(window.attachEvent) {

	window.attachEvent("onload", smartOver);

}

else{

	window.onload = smartOver;

}