<script>
var c3 = (Visit.customAttributes.c3);
var ifrm = document.createElement('iframe');
ifrm.setAttribute('id', 'ifrm'); // assign an id
document.body.appendChild(ifrm); // to place at end of document
// assign url
ifrm.setAttribute('src', 'https://www.smptrack.com/rd/ipx.php?hid=' + c3 + '&sid=2014&transid=ZANv2');
</script>