Why am I getting an OPTIONS request instead of a GET request?

Question

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.js" type="text/javascript"></script> <script> $.get("http://example.com/", function(data) {      alert(data); }); </script> 

it does an OPTIONS request to that URL, and then the callback is never called with anything.

When it isn't cross domain, it works fine.

Shouldn't jQuery just make the call with a <script> node and then do the callback when its loaded? I understand that I won't be able to get the result (since it is cross domain), but that's OK; I just want the call to go through. Is this a bug, or am I doing something wrong?

Answer 1

According to MDN,

Preflighted requests

Unlike simple requests (discussed above), "preflighted" requests first send an HTTP OPTIONS request header to the resource on the other domain, in order to determine whether the actual request is safe to send. Cross-site requests are preflighted like this since they may have implications to user data. In particular, a request is preflighted if:

• It uses methods other than GET or POST. Also, if POST is used to send request data with a Content-Type other than application/x-www-form-urlencoded, multipart/form-data, or text/plain, e.g. if the POST request sends an XML payload to the server using application/xml or text/xml, then the request is preflighted.
• It sets custom headers in the request (e.g. the request uses a header such as X-PINGOTHER)

Answer 2

The OPTIONS is from http://www.w3.org/TR/cors/ See http://metajack.im/2010/01/19/crossdomain-ajax-for-xmpp-http-binding-made-easy/ for a bit more info