var imageDir = "images/";
var imgnum = 5;
var imgs = new Array(imgnum);
function preLoad() {
	for (var i=0; i<imgnum+1; i++) {
		imgs[i] = new Image();
		if((i > 0) && (i < 4)){
			imgs[i].src = imageDir + "menu" + i + "_jp2.gif";
		}else{
			imgs[i].src = imageDir + "menu" + i + "_jp.gif";
		}
	}
}
function enImg(id, n) {
	if((n > 0) && (n < 4)){
		document.images[id].src = imageDir + "menu" + n + "_en2.gif";
	}else{
		document.images[id].src = imageDir + "menu" + n + "_en.gif";
	}
}
function jpImg(id, n) {
	if((n > 0) && (n < 4)){
		document.images[id].src = imageDir + "menu" + n + "_jp2.gif";
	}else{
		document.images[id].src = imageDir + "menu" + n + "_jp.gif";
	}
}