Why does CORS not work with POST?

Question

Mozilla's own specification says that it should be simple GETor POSTshould initially be CORS without first checking, but so far every attempt POSTI've made has resulted in a header OPTIONS. When I change it from POSTto get the code, it immediately sends the correct request GETso that part of the cross site works fine.

Here is an example of what I'm doing in firefox:

 var destinationUrl = 'http://imaginarydevelopment.com/postURL';
 var invocation = new XMLHttpRequest();
            if (invocation) {
                invocation.open('POST', destinationUrl, true);
                //tried with and without this line
                //invocation.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

                invocation.onreadystatechange = (function Handler() {
                if (invocation.readyState == 4)
                        alert('Request made');
                });
                invocation.send(/* tried with and without data*/);
            }

Here is what I already worked in chrome and IE:

var destinationUrl = 'http://imaginarydevelopment.com/postURL';
var destination = { url: destinationUrl, type: 'POST', success: AjaxSuccess, error: AjaxError,
            dataType: 'text', contentType: 'application/x-www-form-urlencoded'
        };
  destination.data = { 'rows': rowList, 'token': token };
            $jq.ajax(destination);

Answer 1

, , , text/plain :

var destination = { url: destinationUrl, type: 'POST', success: AjaxSuccess, error: AjaxError,
             contentType: 'text/plain'
        };
var postData={ 'anArray': theArray, 'token': token };
            destination.data=JSON.stringify(postData);

$jq.ajax(destination);

, -, , 505. Access-Control-Allow-Origin: * , .

Answer 2

https://developer.mozilla.org/En/HTTP_Access_Control

, enctype / Fx4 + .