function initRollOvers() {

	if (!document.getElementById){

		return;

	}

	

	var preLoads = new Array();

	var allImages = document.getElementsByTagName('img');



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

		if (allImages[i].className == 'rollover') {

			var src = allImages[i].getAttribute('src');

			var ftype = src.substring(src.lastIndexOf('.'), src.length);

			var oSrc = src.replace(ftype, '_on'+ftype);



			//-- スワップ元、スワップ先画像の登録

			allImages[i].setAttribute('pSrc', src);

			allImages[i].setAttribute('oSrc', oSrc);



			//-- イメージのプリロード

			preLoads[i] = new Image();

			preLoads[i].src = oSrc;



			//-- イベントの設定

			allImages[i].onmouseover = function() {

				this.setAttribute('src', this.getAttribute('oSrc'));

			}

			allImages[i].onmouseout = function() {

				this.setAttribute('src', this.getAttribute('pSrc'));

			}

		}

	}

}



window.onload = initRollOvers;