Can I post JSON without using AJAX?

1. Create an HTML form with unique "id" attribute. You can hide it using CSS "display:none". Also fill the action and method attributes.
2. Add a text or hidden input field to the form. make sure you give it a meaningful "name" attribute. That's the name that the server would get the data within.
3. Using JQuery (or plain old javascript) copy the variable "dat" into the input field
4. Submit the form using script

There is a working draft to support the so called HTML-JSON-FORMS, see: http://www.w3.org/TR/2014/WD-html-json-forms-20140529/

So far use ajax or send the json into an input text field.

<form action="xxx.aspx" method="POST">
  <input type='hidden' id='dat' />

  <!-- Other elements -->
</form>

<script type='text/javascript'>
  $('#dat').val(JSON.stringify(frm.serializeArray()));
</script>