function changefontsize(size) {
  setActiveStyleSheet(size);
  changeImage(size);
}

function changeImage(size) {
  try
  {
    var imageHTML = document.getElementById("text-resize");
    imageHTML.innerHTML = imageHTML.innerHTML.replace(/_on/,"_off");

    var imageChange = document.getElementById(size);
    if (imageChange == null || imageChange == "") {
      imageChange = document.getElementById("medium");
    }
    imageChange.innerHTML = imageChange.innerHTML.replace(/_off/,"_on");
  }
  catch(e)
  {
    // Alert("error in function changeImage(size)");
  }
}
function textLarger()
{
  var current_size = getActiveStyleSheet();
  switch(current_size)
  {
    case("small"):
      setActiveStyleSheet("medium");
      break;
    case("medium"):
      setActiveStyleSheet("large");
      break;
    case("large"):
      setActiveStyleSheet("xlarge");
      break;
    case("xlarge"):
      setActiveStyleSheet("xlarge");
      break;
    default:
      setActiveStyleSheet("large");
      break;
  }
}
function textSmaller()
{
  var current_size = getActiveStyleSheet();
  switch(current_size)
  {
    case("xlarge"):
      setActiveStyleSheet("large");
      break;
    case("large"):
      setActiveStyleSheet("medium");
      break;
    case("medium"):
      setActiveStyleSheet("small");
      break;
    case("small"):
      setActiveStyleSheet("small");
      break;
    default:
      setActiveStyleSheet("small");
      break;
  }
}

function setActiveStyleSheet(title) {
  var a = document.getElementById('container');
  switch (title)
  {
    case "small":
      a.style.fontSize = "85%";
      break;
    case "medium":
      a.style.fontSize = "100%";
      break;
    case "large":
      a.style.fontSize = "120%";
      break;
    case "xlarge":
      a.style.fontSize = "140%";
      break;
  }
}

function getActiveStyleSheet() {
  var a = document.getElementById('container').style.fontSize;
  switch (a)
  {
    case "85%":
      return "small";
      break;
    case "100%":
      return "medium";
      break;
    case "120%":
      return "large";
      break;
    case "140%":
      return "xlarge";
      break;
  }
}

function getPreferredStyleSheet() {
  return ("medium");
}

function setContrast(title)
{
  try
  {
    var i, a;
    // Run through all the links in the page
    for (i=0; (a = document.getElementsByTagName("link")[i]); i++)
    {
      // If this is an alternate stylesheet then
      if (a.getAttribute("rel").indexOf("alternate stylesheet") != -1)
      {
        if (a.getAttribute("title").indexOf("contrast") != -1)
        {
          // disable the stylesheet
          a.disabled = true;
          // if it is the chosen stylesheet
          if (a.getAttribute("title") == title)
          {
            a.disabled = false;
          }
        }
      }
    }
  }
  catch(e)
  {
    // Error
  }
  createCookie("contrast", title, 365);
}

function createCookie(name,value,days) {
  if (days) {
    var date = new Date();
    date.setTime(date.getTime()+(days*24*60*60*1000));
    var expires = "; expires="+date.toGMTString();
  }
  else expires = "";
  document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');
  for(var i=0;i < ca.length;i++) {
    var c = ca[i];
    while (c.charAt(0)==' ') c = c.substring(1,c.length);
    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  }
  return null;
}

window.onload = function(e) {
  var cookie = readCookie("style");
  var title = cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);
  changeImage(title);

  cookie = readCookie("contrast");
  title = cookie ? cookie : "normalcontrast"
  setContrast(title);
}

window.onunload = function(e) {
  var title = getActiveStyleSheet();
  createCookie("style", title, 365);
}

// http://www.alistapart.com/articles/alternate/