function addEvent(obj, evType, fn){
 if (obj.addEventListener){
    obj.addEventListener(evType, fn, false);
    return true;
 } else if (obj.attachEvent){
    var r = obj.attachEvent("on"+evType, fn);
    return r;
 } else {
    return false;
 }
}
function removeEvent(obj, evType, fn, useCapture){
  if (obj.removeEventListener){
    obj.removeEventListener(evType, fn, useCapture);
    return true;
  } else if (obj.detachEvent){
    var r = obj.detachEvent("on"+evType, fn);
    return r;
  } else {
    alert("Handler could not be removed");
  }
}

function getViewportHeight() {
	if (window.innerHeight!=window.undefined) return window.innerHeight;
	if (document.compatMode=='CSS1Compat') return document.documentElement.clientHeight;
	if (document.body) return document.body.clientHeight; 
	return window.undefined; 
}
function getViewportWidth() {
	if (window.innerWidth!=window.undefined) return window.innerWidth; 
	if (document.compatMode=='CSS1Compat') return document.documentElement.clientWidth; 
	if (document.body) return document.body.clientWidth; 
	return window.undefined; 
}

function swap(listIdPrefix) {
	collapsedList = document.getElementById(listIdPrefix + "_collapsed");
    expandedList = document.getElementById(listIdPrefix + "_expanded");
    if (collapsedList.style.display == "block") {
        collapsedList.style.display = "none";
   	    expandedList.style.display = "block";
   	} else {
   	    collapsedList.style.display = "block";
   	    expandedList.style.display = "none";
   	}
}