The correct method used for cross-domain Ajax calls is:
JSONP (JSON with Padding)
JSONP allows making cross-domain requests by dynamically injecting a <script> tag.
Example:
$.ajax({
  url: 'https://api.example.com/data?callback=?',
  dataType: 'jsonp',
  success: function(response) {
    console.log(response);
  }
});