Making a HTML form submit to different places

Hoping someone can help with this. I have a form which has an action attribute. This action attribute enables the user to subscribe to a newsletter when the form is submitted.

What I'm trying to do is only use that action if the user has checked a checkbox giving permission to subscribe to the newsletter. If the checkbox is left unchecked, the form can still be submitted, but will be redirected to a separate URL, disregarding the form's action attribute.

So far this is what I have, I'm not great with javascript so any help would be appreciated.

$('#wifi-capture-form').submit(function(e) {
    var wifiConfirm = $(this).attr("data-redirect");  
    if ($('input.newsletter-checkbox').is(':checked')) {

    f24("send", "form", "form.#wifi-capture-form");

    }       

    else (
        f24("send", "form", $(this), function(e) {
        e.preventDefault
        window.location = wifiConfirm;  
        })
    )}
    });
    });

and the form is

<form name="wifi-capture-form" id="wifi-capture-form" action="http://ift.tt/2CFuOhL" method="post" class="f24form wifi-capture-form" data-redirect="https:http://ift.tt/2D4bHPn">

    <label for="fieldName">Name</label><br />
    <input id="fieldName" name="cm-name" class="form-control" type="text" />
    <label for="fieldEmail">Email</label><br/>
    <input id="fieldEmail" class="form-control" name="cm-dkhywr-dkhywr" type="email" required /><br/><br/>

    <input type="checkbox" name="newsletter" class="newsletter-checkbox" id="newsletter" value="Subscribe to newsletter"> Subscribe to our newsletter<br/><br/>

    <button type="submit" class="btn btn-primary">Submit</button>