function pop(url, name, width, height) {
    width=Math.min(screen.availWidth,width);
    height=Math.min(screen.availHeight-40,height);
    var poz_x=(screen.availWidth-width)/2;
    var poz_y=(screen.availHeight-height-30)/2;
    newwin=window.open(url, name, 'scrollbars=yes, menubar=no, width='+width+', height='+height+', resizable=yes,toolbar=no, left='+poz_x+', top='+poz_y+', location=no, status=no');
    newwin.focus();
}