CORS not working on Chrome

what finally worked for me is xhr.setRequestHeader('Content-Type', 'text/plain');

EDIT: The server needs to add Access-Control-Allow-Headers: Content-Type to avoid this problem.

I am coming back to my own question a decade later. I don’t know if this is a good thing or a terrible thing.

I have solved my problem this way:

Add this to your PHP Code:

header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Credentials: true ");
header("Access-Control-Allow-Methods: OPTIONS, GET, POST");
header("Access-Control-Allow-Headers: Content-Type, Depth, User-Agent, X-File-Size, X-Requested-With, If-Modified-Since, X-File-Name, Cache-Control");

Or add these headers to your response.

Problem: The browsers ask to the server for options before your main request, to check if the site has the option to allow comunication with different origin, and then if yes, they do your POST or GET request.

EDIT: Try this (without your hack) to see if you're receiving data...

$.ajax({ url : crossOriginURL,
    type : "GET",
    error : function(req, message) {
        alert(message);
    },
    success : function(data) {
        alert(data);
    },
    dataType :  "text"} );