function chgImg(name,url) {
	document.images[name].src = url;
	}

function preLoad(e) {
	var allimg = new Image();
	allimg[0] = "../i/btn_about01_ro.gif";
	allimg[1] = "../i/btn_about02_ro.gif";
	allimg[2] = "../i/btn_about03_ro.gif";
	allimg[3] = "../i/btn_about04_ro.gif";

	btnimg = new Array();
	//配列にイメージオブジェクトの格納とプリダウンロード
	for(var cnt=0; cnt < allimg.length; cnt++) {
		if(allimg[cnt]!=""){
			btnimg[allimg[cnt]] = new Image();
			btnimg[allimg[cnt]].src = allimg[cnt];
			}
		}
	}


if(window.addEventListener)window.addEventListener('load',preLoad,false);
if(window.attachEvent)window.attachEvent('onload',preLoad);