function popwin(url, w, h, options) {
	var winleft = (screen.width - w) / 2;
	var wintop = (screen.height - h) / 2;
	
	if(!options) {
		var options = 'status=no,resizable=no,scrollbars=no,menubar=no,toolbar=no';
	}
	options = options + ', width=' + w + ',height=' + h + ',top=' + wintop + ',left=' + winleft + '';
	window.open(url, 'newwin', options);
}

function lightup(imageobject, opacity) {
	if(navigator.appName.indexOf("Netscape")!= -1 && parseInt(navigator.appVersion) >= 5) {
    imageobject.style.MozOpacity = opacity / 100;
	} else if (navigator.appName.indexOf("Microsoft") != -1 && parseInt(navigator.appVersion) >= 4) {
    imageobject.filters.alpha.opacity = opacity;
	}
}