var isDOM = document.getElementById ? true : false;
var isIE4 = document.all ? true : false;
var isNS4 = document.layers ? true : false;

function getRef(name)
{
  if (isDOM) return document.getElementById(name);
  if (isIE4) return document.all[name];
  if (isNS4) return document.layers[name];
}
function getStyRef(ref) { return ((isNS4 || ref == null) ? ref : ref.style); }
function getSty(id) { return getStyRef(getRef(id)); };

pics = new Array();
var pocet = 0;
function preload(prvni, druhy) {
  pics[pocet] = new Array(1);
  pics[pocet][0] = new Image();
  pics[pocet][0].src = prvni;
  pocet++;
}
var preload_img = new Array(
);

for (soubor in preload_img)
{
  preload('./img/' + preload_img[soubor]);
}

function hyperlink(url) { window.location=url; }

function targetBlank(url)
{
  var width = 800;
  var height = 600;
  var left = Math.floor( (window.screen.availWidth - 10 - width) / 2);
  var top = Math.floor( (window.screen.availHeight - 20 - height) / 2);
  var href = (typeof(url) == 'string') ? url : url.href;

	if (href != "")
	{
    var winParms = "screenX=" + left + ",screenY=" + top + ",top=" + top + ",left=" + left + ",height=" + height + ",width=" + width;
		return !window.open(href,'_blank', 'menubar=yes,toolbar=yes,location=yes,directories=no,fullscreen=no,titlebar=yes,hotkeys=yes,alwayslowered=no,status=yes,scrollbars=yes,resizable=yes,dependent=no,channelmode=NO,alwaysraised=yes,zlock=yes,'+winParms);
	}
}

function openNahled(url) {
    return window.open(url, 'openNahled');
}

function sw(id)
{
  var item = getSty(id);
  if (item)
  {
    if (item.display == 'block')
      item.display = 'none';
    else
      item.display = 'block';
  }
  return (item == null);
}

function printPage()
{
  window.print();
  return false;
}

var bOver = false;
var iUpozAktiv = 0;
var iUpozCelkem = 5;
function swUpoz()
{
  if (bOver == false)
  {
    // schovej starné upozornění
    sw('upoz'+iUpozAktiv);
    iUpozAktiv = (iUpozAktiv + 1) % iUpozCelkem;
    // zobraz nové upozornění
    sw('upoz'+iUpozAktiv);
  }
  setTimeout( 'swUpoz();', 2000);
}

function upozOver(bParOver)
{

  bOver = bParOver;
}

window.onload =  function() {
  // zobraz první upozornění
  sw('upoz'+iUpozAktiv);
  setTimeout( 'swUpoz();', 2000);
  sw('upozorneni');
  if (typeof(initsnow) == 'function') initsnow();
}