var agent = navigator.userAgent;
var appver = navigator.appVersion;
var nav = navigator.appName;
var plf = null;
var ver = null;
if(agent.indexOf('Mac') != -1){
	plf = "Mac";
}else if(agent.indexOf('Win') != -1){
	plf = "Win";
}else{
	plf = "other";
}
if(agent.indexOf('MSIE') == -1){
	ver = appver.charAt(0);
	if(nav == "Netscape"){
			nav = "NN";
	}
}else{
	ver = agent.charAt(agent.indexOf('MSIE') + 5);
	nav = "MSIE";
}
		
var imageDir = "images/";
var loadList;
var action = "off";

function preLoad() {
	loadList = new Array("menu01_on.gif", "menu02_on.gif", "menu03_on.gif", "menu04_on.gif", "menu05_on.gif", "menu06_on.gif");
	onImages = new Array();
	for (field in loadList){
		onImages[field] = new Image();
		onImages[field].src = imageDir + loadList[field];
	}
	action = "on";
}

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