function centerpopup(URL,width,height){
	if (parseInt(navigator.appVersion) >= 3){
		if (navigator.appName == "Netscape" && parseInt(navigator.appVersion)<5){
			var tools = new Packages.java.awt.Toolkit.getDefaultToolkit();
			screen=tools.getScreenSize();
		}
		x = screen.width;
		y = screen.height;
	}
window.open(URL,"dummy","scrollbars=yes,top=" + parseInt(y/2-height/2-16) + ",left=" + parseInt(x/2-width/2-5) + ",width=" + width + ",height=" + height );
}