if(document.images)
{
<!-- On & Off -->

btn_Video4a = new Image;
btn_Video4a.src = "images/Video4a.jpg";
btn_Video4b = new Image;
btn_Video4b.src = "images/Video4b.jpg";

btn_Video1a = new Image;
btn_Video1a.src = "images/Video3a.jpg";
btn_Video1b = new Image;
btn_Video1b.src = "images/Video3b.jpg";

btn_Video2a = new Image;
btn_Video2a.src = "images/Video2a.jpg";
btn_Video2b = new Image;
btn_Video2b.src = "images/Video2b.jpg";

}

function chkVer(imagename,objectsrc)
	{
	var n=navigator.appName
	var v=parseInt(navigator.appVersion)
	var browsok=((n=="Netscape")&&(v>=3))
	var browsok2=((n=="Microsoft Internet Explorer")&&(v>=4))
	if ((browsok)||(browsok2))
	document.images[imagename].src=eval(objectsrc + ".src")
	}