function s(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("vzhstyle");
  var title = cookie ? cookie : getPreferredStyleSheet();
  InsertMenu();
  s(title);
}

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

var cookie = readCookie("vzhstyle");
var title = cookie ? cookie : getPreferredStyleSheet();
s(title);

function InsertMenu() {
 var MenCon = document.getElementById('MenuContent');
 if (MenCon != null) {
  MenCon.innerHTML = '<table border="0" cellspacing="1" cellpadding="0" onmouseover="menuin();" onmouseout="menuweg();" id="tob"><tr><td title="Selecteer een stijl" class="men">&nbsp;Stijl&nbsp;</td><td id="vn" class="sel" onclick="s(\'VZH standaard\');" title="Normale letters"></td></tr><tr><td></td><td id="vg" class="sel" onclick="s(\'Grote letters\');" title="Grote letters"></td></tr><tr><td></td><td id="vw" class="sel" onclick="s(\'Geen achtergrond of marges\');" title="Geen marges"></td></tr><td></td><td id="vd" class="sel" onclick="s(\'Donker, Wit op zwart\');" title="Donker, Wit op zwart"></td></tr></table>'; }
 }

function menuin() {
 var nm = document.getElementById('vn');
 var gm = document.getElementById('vg');
 var wm = document.getElementById('vw');
 var dm = document.getElementById('vd');
 nm.innerHTML = '&nbsp;Normaal&nbsp;';
 gm.innerHTML = '&nbsp;Groot&nbsp;';
 wm.innerHTML = '&nbsp;Randen&nbsp;<br />&nbsp;weg';
 dm.innerHTML = '&nbsp;Donker&nbsp;';
 }

function menuweg() {
 var nm = document.getElementById('vn');
 var gm = document.getElementById('vg');
 var wm = document.getElementById('vw');
 var dm = document.getElementById('vd');
 nm.innerHTML = '';
 gm.innerHTML = '';
 wm.innerHTML = '';
 dm.innerHTML = '';
 }