disableCookies does not work (no replies)

Hello,

I tried to stop piwik from setting cookies.
I followed this instruction: [piwik.org]
But still some cookies are set: _pk_cvar, _pk_id, _pk_ref and _pk_ses

I do use Piwik 2.10.0

This is my trackingcode:

<!-- Piwik -->
<script type="text/javascript">
  var _paq = _paq || [];
  _paq.push(['disableCookies']);
  _paq.push(['trackPageView']);
  _paq.push(['enableLinkTracking']);
  
  (function() {
    var u="//www.sven-lewerentz.de/piwik/";
    _paq.push(['setTrackerUrl', u+'piwik.php']);
    _paq.push(['setSiteId', 1]);
    var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
    g.type='text/javascript'; g.async=true; g.defer=true; g.src=u+'piwik.js'; s.parentNode.insertBefore(g,s);
  })();
</script>
<noscript><p><img src="//www.sven-lewerentz.de/piwik/piwik.php?idsite=1" style="border:0;" alt="" /></p></noscript>
<!-- End Piwik Code -->

Any idea why it is not working? Thanks in advance!

Sven