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

function highlightchnav() {
  if (!document.getElementsByTagName) return false;
  if (!document.getElementById) return false;
  if (!document.getElementById("menu")) return false;
  var nav = document.getElementById("chapter-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;
  //  alert(linkurl);
  //  alert(currenturl);
    if (currenturl.indexOf(linkurl) != -1) {
      links[i].className = "here";
      links[i].parentNode.className = "current";
      var linktext = links[i].lastChild.nodeValue.toLowerCase();
      document.body.setAttribute("id",linktext);
    }
  }
}


function gohome() {
window.location.href='/';
}

function gosomewhere(requrl) {
window.location.href=requrl;
}

function clickablehome() {
  if (!document.getElementsByTagName) return false;
  if (!document.getElementById) return false;
  if (!document.getElementById("homelink")) return false;
  var mastheadlink = document.getElementById("homelink");
  mastheadlink.onclick = function() {
   gohome();
   return false;
  }
}

function clickablestressed() {
  if (!document.getElementsByTagName) return false;
  if (!document.getElementById) return false;
  if (!document.getElementById("stressed")) return false;
  var stressedlink = document.getElementById("stressed");
  stressedlink.onclick = function() {
   gosomewhere('/stressed.php');
   return false;
  }
}

addLoadEvent(clickablehome);
addLoadEvent(highlightPage);
addLoadEvent(highlightchnav);