var imageDir = _dir + "common/image/";
	var preLoadList;
	var action = "false";

	function preLoad(){
		preLoadList = new Array(
			"header_navi0001d.gif","header_navi0001e.gif",
			"header_navi0002d.gif","header_navi0002e.gif",
			"header_navi0003d.gif","header_navi0003e.gif",
			"header_navi0004d.gif","header_navi0004e.gif",
			"header_navi0005d.gif","header_navi0005e.gif");
		onImages = new Array();
		for(field in preLoadList){
			onImages[field] = new Image();
			onImages[field].src = imageDir + preLoadList[field];
		}
		action = "true";
	}

	function changeImage(fileName, imageName){
		if (action == "true"){
			document.images[imageName].src = imageDir + fileName;
		}
	}