function showSub(c, id, a) {
	var _realyShow = (a.className == 'active ex') ? false : true;
	
	// shovame vsechny
	for (i = 1; i <= c; i++) {
		if (obj = document.getElementById('subbl'+i))
			obj.style.display = 'none';
		if (obj = document.getElementById('abl'+i)) 
			obj.className = 'ex';
	}
	
	// pokud 
	if (document.getElementById('sub'+id)) {
		if (_realyShow) {
			document.getElementById('sub'+id).style.display = 'block';
			a.className = 'active ex';
		}
		return true;
	}
	return false;
}