Responsive Google Plus Widget

gplus.html

<div class="gp-wrap" id="gp-wrap">
    <div class="g-page" data-href="https://plus.google.com/102226233421872956936" data-rel="publisher"></div>
    <script type="text/javascript">
      (function() {
        // this guy right here
        document.getElementsByClassName('g-page')[0].setAttribute('data-width', document.getElementById('gp-wrap').clientWidth);
        var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true;
        po.src = 'https://apis.google.com/js/platform.js';
        var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s);
      })();
    </script>
</div>