Array.prototype.inArray = function (value)
// Returns true if the passed value is found in the
// array.  Returns false if it is not.
{
    var i;
    for (i=0; i < this.length; i++) {
        // Matches identical (===), not just similar (==).
        if (this[i] === value) {
            return true;
        }
    }
    return false;
};

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

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) {
addLoadEvent( 
  function(e) {
    var cookie = readCookie("style");
    title = cookie ? cookie : getPreferredStyleSheet();
    setActiveStyleSheet(title);
  }
);

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

var color = new Array('normal','gross');
var cookie = readCookie("style");
var title = cookie ? cookie : getPreferredStyleSheet();
//alert(title);
if(title == null || title == '') 
{
  var ntake = Math.round(0 + 4*(Math.random()) );
  var title = color[ntake]; 
  // naechste Zeile auskommentieren um Zufallfarbe zu bekommen
  title = 'normal';
}
setActiveStyleSheet(title);
createCookie("style", title, 365);
//alert(title);