AJAX/PHP POST retrieval

I'm doing a POST using AJAX and I'm checking for the response with PHP using

if (!empty($_POST)

but it doesn't seem to be hitting the if or else.

The form is submitting and I get a 200 status in the network tab.

PHP isn't my main language so I'm wondering if I'm missing something relatively simple?

Thanks

Form:

<form id="myForm" method="post" novalidate="novalidate">
    ...
    <button type="submit" name="contact_send">Send</button>
</form>

AJAX:

jQuery.ajax({
    type: 'POST',
    url: window.location.href,
    data: formData,
    success: function(response) {
        console.log('response');
    }
});

PHP:

if (!empty($_POST)) {
    print_r('Data');
    add_action('init', 'deliver');
} else {
    print_r('No Data');
}

Neither the if or else is reached