Asynchronous Tweet Button
<a href="http://twitter.com/share" class="twitter-share-button" data-count="vertical">Tweet</a>
<!-- Put this JS at the bottom of the page -->
<script id="deferedjs" type="text/javascript">
var b = document.createElement('script');
b.type = 'text/javascript';
b.src = ('http://platform.twitter.com/widgets.js');
var a=document.getElementById("deferedjs");
a.parentNode.insertBefore(b,a);
</script>