How to send data in the HTTP request body when using an HTML form?

Question

The HTTP spec says that a POST request can contain an arbitrary body of data.

An HTML form element can POST to a URL and may contain input elements, but those input elements get turned into a query string.

How can I get a form to also send along data in the body of the HTTP POST request that it sends when its submit button is pressed?

Edit: While this question is quite happily independent of any other question, it is related to http://stackoverflow.com/questions/2925796/post-xml-to-server-receive-pdf

Somehow, I want to be able to send data in a POST's body, and I want the browser to automagically handle the HTTP response (which will be an application/pdf). This question is phrased in such a way that I am hoping I can avoid using XmlHttpRequest (AJAX) and just use the browser's built-in behaviour with form elements to properly submit data and handle the PDF that is sent back.

Answer 1

Have you specified method="post" in your form element? It sounds like you're sending a get request.

Answer 2

Use javascript to send an ajax request when the button is pressed and cancel the form submission. Form submits will always be name/value pairs. XForms can send customized data but if this is for public use it'll be years before XForms is supported by the majority of browsers in use, if ever.