Method=POST on form

The following is portion of my websites code for a form script that parses customer details to a third party mail-forwarder via POST method.

Unfortunately the form doesn't go anywhere - however testing the code on there website works perfectly.

Could this be something to do with my 'main.js' file?

Apologies for how newb this is but appreciate any help I can get.

Thank you

<!-- Signup Form -->
        <form id="signup-form" method="POST" action="http://ift.tt/2l8W4Mq">
        <input type="hidden" name="_subject" value="New submission!" />
        <input type="text" name="_gotcha" style="display:none" />
        <input type="text" name="Name" id="Name" placeholder="Name" />
        <input type="email" name="_replyto" id="email" placeholder="Email Address" />
        <input type="text" name="Name" id="mobile number" placeholder="Mobile Number" />
        <input type="submit" value="Sign Up" />
        </form>