function setActiveStyleSheet(title) {
  var i, a, main;
  if (title) {
    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);