Origin is not allowed by Access-Control-Allow-Origin

Question

I'm making an Ajax.request to a remote PHP server in a Sencha Touch 2 application (wrapped in PhoneGap).

The response from the server is the following:

XMLHttpRequest cannot load http://nqatalog.negroesquisso.pt/login.php. Origin http://localhost:8888 is not allowed by Access-Control-Allow-Origin.

How can I fix this problem?

Answer 1

I wrote an article on this issue a while back, Cross Domain AJAX.

The easiest way to handle this if you have control of the responding server is to add a response header for:

Access-Control-Allow-Origin: * 

This will allow cross-domain Ajax. In PHP, you'll want to modify the response like so:

<?php header('Access-Control-Allow-Origin: *'); ?> 

You can just put the Header set Access-Control-Allow-Origin * setting in the Apache configuration or htaccess file.

It should be noted that this effectively disables CORS protection, which very likely exposes your users to attack. If you don't know that you specifically need to use a wildcard, you should not use it, and instead you should whitelist your specific domain:

<?php header('Access-Control-Allow-Origin: http://example.com') ?>