You can use this code instead :
<div class="g-plusone" data-annotation="inline" data-width="300"></div>
Javascript :
window.___gcfg = {lang: 'da'};
(function() {
var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true;
po.src = 'https://apis.google.com/js/plusone.js';
var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s);
})();
Result : http://jsfiddle.net/L3XR7/