function setActiveStyleSheet(title) {
 
  if (title == null) {
	title = 'algemeen_pagina';
  }

  var i, a, main, iReturn;
  iReturn = 0;
  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").replace(/^\s*|\s*$/g,"") == title.replace(/^\s*|\s*$/g,"")) 
      {
      a.disabled = false;
      iReturn = 1; 
      }
    }
  }
  return iReturn;
}

function switchStyleSheets(title, title2) {  
	var active;

	active = getActiveStyleSheet(title)
	
	if (active == title) {
		setActiveStyleSheet(title2);
	}
	else {
		setActiveStyleSheet(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) {
 try {
  var cookie = readCookie("style");
  if (cookie=='null') {cookie=0}
  var title = cookie ? cookie : getPreferredStyleSheet();
  if(setActiveStyleSheet(title)==0) { setActiveStyleSheet(getPreferredStyleSheet()); }
 } catch (e) {
	//forget it!
 }
}

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