Example: Submit post requests across domains using an intermediary targeted Iframe.

example-post-ajax-through-iframe.html

<form action="http://anotherdomain/save" method="post" target="myiframe" id="myform">
    <!-- standard form here -->
</form>
<iframe src="about:blank" name="myiframe" style="display: none;"></iframe>

<!-- Then, javascript something like: -->

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js"></script>

<script>
  $(document).ready(function(){
    $('#myform').on('submit', function(e){
        e.preventDefault();
        //if(validates){
          $(e).submit();
        // }
      });
  });
</script>