TF - How to set up the JavaScript in a form

JS in a form.js

<script type="text/javascript">
(function() {
    var field = 'xxTrustedFormCertUrl';
    var provideReferrer = false;
    var tf = document.createElement('script');
    tf.type = 'text/javascript'; tf.async = true; 
    tf.src = 'http' + ('https:' == document.location.protocol ? 's' : '') +
    '://api.trustedform.com/trustedform.js?provide_referrer=' + escape(provideReferrer) + '&field=' + escape(field) + '&l='+new Date().getTime()+Math.random();
    var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(tf, s); }
)();
</script>
<noscript>
    <img src="http://api.trustedform.com/ns.gif" />
</noscript>