function zobrazSkryj(idecko){
  el=document.getElementById(idecko).style; 
  el.display=(el.display == 'block')?'none':'block';
  }

function login(showhide){
  if(showhide == "show"){
      document.getElementById('popupbox').style.visibility="visible";
      document.getElementById('login').focus()
  }else if(showhide == "hide"){
      document.getElementById('popupbox').style.visibility="hidden"; 
  }
}