function setStyleSheet(title)
{
  var i, stylesheet;
  for(i=0; (stylesheet = document.getElementsByTagName("link")[i]); i++)
  {
    if(stylesheet.getAttribute("rel").indexOf("style") != -1 && stylesheet.getAttribute("title"))
    {
      stylesheet.disabled = true;
      if(stylesheet.getAttribute("title") == title) stylesheet.disabled = false;
    }
  }  
}

function getActiveStyleSheet()
{
  var i, stylesheet;
  for(i=0; (stylesheet = document.getElementsByTagName("link")[i]); i++)
  {
    if(stylesheet.getAttribute("rel").indexOf("style") != -1 && stylesheet.getAttribute("title") && !stylesheet.disabled) 
    {
      return stylesheet.getAttribute("title");
    }
  }
  return null;
}

function getPreferredStyleSheet()
{
  var i, stylesheet;
  for(i=0; (stylesheet = document.getElementsByTagName("link")[i]); i++)
  {
    if(stylesheet.getAttribute("rel").indexOf("style") != -1 && stylesheet.getAttribute("rel").indexOf("alt") == -1 && stylesheet.getAttribute("title"))
    {
      return stylesheet.getAttribute("title");
    }
  }
  return null;
}

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

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

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

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

var cookie = readCookie("style");
var title = cookie ? cookie : getPreferredStyleSheet();
setStyleSheet(title);