function skryjbutton(idecko){
  if (document.getElementById('mnozstvi' + idecko).value < 100)
  {
  /*
    el=document.getElementById('pridat' + idecko).style;
    el.display='none';
    */

    el=document.getElementById('pridat' + idecko).style;
    el.visibility='hidden';

    otevri_okno('okno2.php');
  }
}

function otevri_okno(adresa)
{
//window.open(adresa , 'nove_okno', 'toolbar=no, menubar=no, location=no, directories=no, scrollbars=yes, resizable=yes, status=no, width=600, height=350, top=200, left=100');
window.open(adresa, "_blank", "width=320,height=320")
}

function navraceni(idecko){
  if (document.getElementById('mnozstvi' + idecko).value >= 100)
  {
    el=document.getElementById('pridat' + idecko).style;
    el.visibility='visible';
  }
}