jquery form submits twice - forms

Question

I've created a form submit with ajax, but it submits twice???
Is there anyone who knows whats going wrong?
This is my code:
var form = $('#myForm'); // contact form
var submit = $('#offertesturen'); // submit button
var alert = $('.alert'); // alert div for show alert message
$('#myForm')
.on('invalid.fndtn.abide', function () {
var invalid_fields = $(this).find('[data-invalid]');
console.log(invalid_fields);
})
.on('valid.fndtn.abide', function(e) {
e.preventDefault(); // prevent default form submit
$.ajax({
url: 'send_form_email.php', // form action url
type: 'POST', // form submit method get/post
dataType: 'html', // request type html/json/xml
data: form.serialize(), // serialize form data
beforeSend: function() {
alert.fadeOut();
submit.html('.....'); // change submit button text
},
success: function(data) {
alert.html(data).fadeIn(); // fade in response data
form.trigger('reset'); // reset form
submit.html('Aanvragen!'); // reset submit button text
$(document).scrollTop(0);
$('#secondModal').foundation('reveal', 'open');
},
error: function(e) {
console.log(e)
}
});
});