function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}

function showSection(id, theLink) {
  var divs = document.getElementsByTagName("div");
  for (var i=0; i<divs.length; i++ ) {
    if (divs[i].className.indexOf("section") == -1) continue;
    if (divs[i].getAttribute("id") != id) {
      divs[i].style.display = "none";
    } 
    else {
      divs[i].style.display = "block";
    }
  }
  var theContainer = document.getElementById("tabnav");
  var theLinks = theContainer.getElementsByTagName("a");
  for (var j=0; j<theLinks.length; j++){
  	if (theLinks[j].getAttribute("href").split("#")[1] == id){
  		theLinks[j].className="active";
  	}
  	else{
  		theLinks[j].className=" ";
  	}
  }
}

function prepareInternalnav() {
  if (!document.getElementsByTagName) return false;
  if (!document.getElementById) return false;
  if (!document.getElementById("tabnav")) return false;
  var nav = document.getElementById("tabnav");
  var links = nav.getElementsByTagName("a");
  for (var i=0; i<links.length; i++ ) {
    var sectionId = links[i].getAttribute("href").split("#")[1];
    var theLink = links[i];
    if (!document.getElementById(sectionId)) continue;
    if (links[i].getAttribute("href") != "#featured1"){
    document.getElementById(sectionId).style.display = "none";
    }
    else{
    links[i].className="active";
   	}
    links[i].destination = sectionId;
    // change onmouseover to onclick for different user action
    links[i].onclick = function() {
      showSection(this.destination, theLink);
      return false;
    }
  }
}
function createNavigation(){
  if (!document.getElementsByTagName) return false;
  if (!document.getElementById) return false;
  var tabNav = document.createElement("ul");
  tabNav.setAttribute("id", "tabnav");
  var theSections = document.getElementsByTagName("div");
  for (var i=0; i<theSections.length; i++){
  	sectionClass = theSections[i].className;
  	relatedLink = theSections[i].getAttribute("id");
  	if (sectionClass == "section"){
    		theHeaders = theSections[i].getElementsByTagName("h3");
    		theText = theHeaders[0].innerHTML;
  		var listItem = document.createElement("li");
  		var theLink = document.createElement("a");
  		var theText = document.createTextNode(theText);
  		theLink.setAttribute("href", "#" + relatedLink);
  		theLink.appendChild(theText);
  		listItem.appendChild(theLink);
  		tabNav.appendChild(listItem);
  	}
  }
  var container = document.getElementById("featured");
	if (!container==null) {
  var kid = container.firstChild;
  container.insertBefore(tabNav, kid);
	}
}

addLoadEvent(createNavigation);
addLoadEvent(prepareInternalnav);