@Charles Halliday so that makes sense and I replaced

return url

with

document.getElementById('ns_form').action = url;

. How would I properly use that with the form code? Is

onSubmit

needed?

<form id="ns_form" action="https://forms.na3.netsuite.com/app/site/crm/externalleadpage.nl?compid=xxx&formid=xxxxxxx" method="post" onSubmit="appendNSParams();">
  <input name="email" type="email" required>
  <input type="submit" value="SUBMIT" class="ns-button primary large">
</form>