var bMouseOver = true;
		 
 browserName = navigator.appName;
 browserVersion = parseInt (navigator.appVersion);
 if (browserName == "Microsoft Internet Explorer"  && browserVersion < 4)
 {
	bMouseOver = false;
 }

function  img_act(imgName) {
	if (bMouseOver) {		
		imgOn = eval(imgName + "on.src");
		document [imgName].src = imgOn;
	}
}

function img_inact(imgName) {
	if (bMouseOver)	{
		imgOff = eval(imgName + "off.src");
		document [imgName].src = imgOff;
	}
}