function zkontrolujEmail(){
	if (window.RegExp) { 
		re = new RegExp("^[_a-zA-Z0-9\.\-]+@[_a-zA-Z0-9\.\-]+\.[a-zA-Z]{2,4}$"); 
		if (!re.test(document.getElementById("email").value)) { 
			window.alert("Emailová adresa nemá správný formát"); 
			return false; 
		} 
	}
}

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

function skryj(idecko){
	el=document.getElementById(idecko).style;
	el.display='none';	
}
function zobraz(idecko){
	el=document.getElementById(idecko).style;
	el.display='block';	
}

function zmenStyl(idecko){
	el=document.getElementById(idecko).style;
	el.backgroundImage =(el.backgroundImage == 'url(/img/list-minus.gif)')
    ?'url(/img/list-plus.gif)'
    :'url(/img/list-minus.gif)';  	
}

function tmidChange() {
  ei=document.getElementById('cislo_option');
  es=document.getElementById('select_tema'); oi=es.selectedIndex;      
  ois = 'group_'+es.options[oi].value; pis='group_'+ei.value;
  if (document.getElementById(pis))
    document.getElementById(pis).style.display = 'none';
  if (document.getElementById(ois)) 
    document.getElementById(ois).style.display = 'block';
  ei.value=es.options[oi].value;
}

// e.folders.length
function CheckAll() {
  var e = document.getElementById('ulohyform');
  for (var i=0;i<e.elements.length;i++)
      {  var ee = e.elements[i];
         if (ee.type == 'checkbox' && ee.name != 'allbox')
            ee.checked = e.allbox.checked;}
}