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

function insertAfter(newElement,targetElement) {
  var parent = targetElement.parentNode;
  if (parent.lastChild == targetElement) {
    parent.appendChild(newElement);
  } else {
    parent.insertBefore(newElement,targetElement.nextSibling);
  }
}

function addClass(element,value) {
  if (!element.className) {
    element.className = value;
  } else {
    newClassName = element.className;
    newClassName+= " ";
    newClassName+= value;
    element.className = newClassName;
  }
}

function highlightPage() {
  if (!document.getElementsByTagName) return false;
  if (!document.getElementById) return false;
  if (!document.getElementById("nav")) return false;
  var nav = document.getElementById("nav");
  var links = nav.getElementsByTagName("a");
  for (var i=0; i<links.length; i++) {
    var linkurl = links[i].getAttribute("href"); 
    var currenturl = window.location.href;
    if (currenturl.indexOf(linkurl) != -1) {
      links[i].className = "purple"; 
      var linktext = links[i].lastChild.nodeValue.toLowerCase();
      document.body.setAttribute("id",linktext);
    }
  }
}

addLoadEvent(highlightPage);