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

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

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

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);
}

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

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