Untitled

<html>
<body>
<script>
    var getParams = window.location.search; // Should look like "?utm_sasi=hummus&utm_R2=D2" etc...
    var iframe = document.createElement('iframe');
    iframe.src = 'https://my.site.com/iframe' + getParams;
    document.body.appendChild(iframe);
</script>
</body>
</html>

// Body of iframe, which should be returned from https://my.site.com/iframe
<html>
<body>
<script>
    var getParams = window.location.search;
    var link = document.createElement('a);
    link.href = 'https://my.site.com/nextPage' + getParams;
    document.body.appendChild(link);
</script>
</body>
</html>