var preLoadFlag = "false";

	function preLoadImg(){
		arrImgList = new Array (
			"../misc/01_on.gif","../misc/02_on.gif","../misc/03_on.gif","../misc/04_on.gif","../misc/05_on.gif","../misc/06_on.gif"
		);
		arrPreLoad = new Array();
		for (i in arrImgList) {
			arrPreLoad[i] = new Image();
			arrPreLoad[i].src = arrImgList[i];
		}
		preLoadFlag = "true";
	}

	function chgImg(fileName,imgName){
		if (preLoadFlag == "true") {
			document.images[imgName].src = fileName;
		}
	}