function openCenteredWindow(targetUrl,windowName,width,height,scrollbars) {
	var winleft = (screen.width - width) / 2;
	var wintop = (screen.height - height) / 2;

	var win = window.open(targetUrl,windowName,'width=' + width + ',height=' + height + ',top=' + wintop + ',left=' + winleft + ',scrollbars=' + scrollbars);

	if (navigator) {
		if (navigator.appVersion) {
			if (parseInt(navigator.appVersion) >= 4) { 
				win.window.focus();
			}
		}
	}
	return false;
}