isDOM=document.getElementById?true:false
isOpera=isOpera5=window.opera && isDOM
isOpera6=isOpera && window.print
isOpera7=isOpera && document.readyState
isMSIE=isIE=document.all && document.all.item && !isOpera
isStrict=document.compatMode=='CSS1Compat'
isNN=isNC=navigator.appName=="Netscape"
isNN4=isNC4=isNN && !isDOM
isMozilla=isNN6=isNN && isDOM
isSafari=(navigator.userAgent.indexOf("Safari") >= 0)

isMac = (navigator.appVersion.indexOf("Mac") != -1);
isMacPPC = (isMac && (navigator.appVersion.indexOf("PPC") != -1 || navigator.appVersion.indexOf("PowerPC") != -1));

function DestrojTreeItem(id_posledneho, cat) {
  if(id_posledneho != cat){
    var obj = document.getElementById('cat'+id_posledneho);
    if (obj){
      obj.style.display = "none";
    }
  }
  return cat;
}

function SwitchTreeItem(cat, is_last) {
	var obj = document.getElementById("cat"+cat);
    if (!obj)
		return false;
     
	var minus_flag = (obj.style.display == "none");
	obj.style.display = (minus_flag ? (isMSIE ? "block" : "") : "none");
}