function addEvent(obj, type, fn) {
  if (obj.addEventListener) {
    obj.addEventListener(type, fn, false);
  } else if (obj.attachEvent) {
    obj["e" + type + fn] = fn;
    obj[type + fn] = function() { obj["e" + type + fn] (window.event); }
    obj.attachEvent("on" + type, obj[type + fn]); 
  }
}

function PokazAkapit(e, id_paragrafu, napis)  {
	var el;	if (window.event && window.event.srcElement) { el = window.event.srcElement; }; if (e && e.target) { el = e.target; }; if (!el) { return; }; (e.preventDefault) ? e.preventDefault() : (e.returnValue = false);

	 var akapit = document.getElementById(id_paragrafu);
	 if (!akapit) return;

	 var view = akapit.style.display == 'none';

	 akapit.style.display = view ? 'block' : "none";
	 if (napis) {
	   el.className = view ? 'fold' : 'expand';
     }
}

function Laduj() {
	var odnosnik = document.getElementById('link');

	var akapit = document.getElementById('nav_txt');
	if (akapit != null) {
		akapit.setAttribute("style", "display: none;");
	
		var akapit2 = document.getElementById('nav2');
		if (akapit2) akapit2.setAttribute("style", "display: block;");
	
		addEvent(odnosnik, 'click', function (e) {
			PokazAkapit(e, 'nav_txt', true);
			PokazAkapit(e, 'nav2', false);
		});
	}
}
addEvent(window, 'load', Laduj);