function otevri_max(url, w, h)
{
    var vlevo = (screen.width-w)/2;
    var zhora = (screen.height-h)/2;
    okno = window.open(url, 'NewWin','resizable=0,top=' + zhora + ',left=' + vlevo + ',menubar=0,status=0,width=' + w + ',height=' + h);
    okno.focus()
}