Posting jquery cloned form fields.

I am working on a project for a client who asked that I add a feature to a form allowing him to add (dynamically) extra fields for multiple phone numbers and/or email addresses. So I simply set up a jquery script to clone the fields on clicking a button. However, when I submit the form only the data in the original field is submitted, the cloned fields are not recognized or are being filtered, because they are not included at all in $_POST. I thought that XSS was the culprit, but it is globally set to false. What am I overlooking. The form is not public facing and is locked behind authentication so XSS is not a concern.