mediagoblin-website/theme/templates/google_custom_search.html

{% if GOOGLE_CUSTOM_SEARCH %}
<script>
  (function() {
    var cx = '{{ GOOGLE_CUSTOM_SEARCH }}';
    var gcse = document.createElement('script'); gcse.type = 'text/javascript'; gcse.async = true;
    gcse.src = (document.location.protocol == 'https:' ? 'https:' : 'http:') +
        '//www.google.com/cse/cse.js?cx=' + cx;
    var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(gcse, s);
  })();
</script>
<div id="google-custom-search" class="nav">
    <gcse:search></gcse:search>
</div>
{% endif %}