function openPopup(url, width, height) {
        var rnd = (Math.round((Math.random()*999)+1));
        var top=Math.round((screen.height-height)/8);
        var left=Math.round((screen.width-width)/8);
        this.open(url, "w"+rnd, "top="+top+",left="+left+",width="+width+",height="+height+",buttons=no,scrollbars=no,location=no,menubar=no,resizable=no,status=no,directories=no,toolbar=no");
}