Let's look at doAjax again, this time modified to send our request JSON:

function doAjax() {
  $('#debug').html("loaded... executing.");
 
  var request = { 
    call: "kf6gpe-7"
  };

  $.ajax({
    type: "POST",
    url: "/",
    data: JSON.stringify(request),
    dataType:"json"
  });
}

</script>
</body>
</html>

The magic line in the previous listing is highlighted; it's the following line in the arguments passed to the ajax method:

    data: JSON.stringify(request),

Of course, we use JSON.stringify to encode the JavaScript object as JSON before assigning it to the data field.