How do I do a POST with jQuery that sends a JSON and not raw query?

Question

I have the following HTML. It is supposed to do a POST to a server (in the MWE below, I just did it with cnn.com).

However, it doesn't do what I expect, which is formatting the POST request in a JSON format. Instead, it gives the following

x1=y1&x2=y2

as the Request Body

while it should give something like

{ "x1": "y1", "x2": "y2"}

for the server to respond properly.

Here is the code:

  <!-- jQuery Version 1.11.0 -->
    <script src="js/jquery-1.11.0.js" }}"></script>

    <!-- Bootstrap Core JavaScript -->
    <script src="js/bootstrap.min.js" }}"></script>

    <!-- Plugin JavaScript -->
    <script src="js/jquery.easing.min.js" }}"></script>
    <script src="js/classie.js" }}"></script>
    <script src="js/cbpAnimatedHeader.js" }}"></script>

    <!-- Contact Form JavaScript -->
    <script src="js/jqBootstrapValidation.js" }}"></script>
<!--
     <script src="js/contact_me.js" }}"></script>
    -->

    <!-- Custom Theme JavaScript -->
    <script src="js/freelancer.js" }}"></script>


<form action="" method="post" name="demoform" id="demoform">

<input type=hidden name=x1 value=y1 id=x1>
<input type=hidden name=x2 value=y2 id=x2>

<input type="button" value="demo" name="button" id="button">

</form>



<script>
 $.sendRequest = function(form) {
                                $.ajax({
                                        type: "POST",
                                        url: "http://www.cnn.com",
                                        data: form.serialize(),
                                        dataType: 'application/json',

                                        success: function(data, textStatus){
                                        }
                                });
   }

 $('#button').click(function () {
                                $.sendRequest($("#demoform"));
                        });
</script>

Just as a note, I want to do the equivalent of:

curl -X POST "https://www.cnn.com" -H  "accept: application/json" -H  "Content-Type: application/json" -d "{  \"x1\": \"y1\", \"x2\": \"y2\"}"

EDIT: I will note that when I do "Inspect" in the browser, and check the request headers, they are not what expected, they have many additional things, and none of the things such as content-type: application/json that I added following the comment below. (instead it shows content-type: text/html). I am not sure why it completely ignores my headers.

Answer 1

 dataType: 'application/json', 

dataType describes the format you expect to receive back from the server and doesn't take a MIME type.

contentType describes the format you are sending.

Change that to:

dataType: "json",
contentType: "application/json",

---

 data: form.serialize(), 

This function URL encodes the data in a form. You need to construct an object and convert it to JSON.

data: JSON.stringify({ foo: "some value", bar: "some value" }),