{{block class="MagentoContactBlockContactForm" name="contactForm" template="Magento_Contact::form.phtml"}}

{{block class="Magento\Cms\Block\Block" block_id="myContact"}}

$('.form.contact').on('submit',function(e){
  e.preventDefault();

  $.ajax({
    url:"<?php /* @escapeNotVerified */ echo $block->getFormAction(); ?>",
    data: $(this).serialize(),
    success: function(){ // it worked },
    error: function(){ // didn't work, why didn't he test his example before posting on SO?? }
  });

});