Ajax requests with different WordPress Address and Site Address setup

I have a user using my plugin with the following wp setup

WordPress Address (URL)
http://server1.theirhost.com/~acct/somewebsite.com/wordpress

Site Address (URL)
http://www.somewebsite.com

I am using admin_url( ‘admin-ajax.php’ ) to pull the ajax url, which returns

http://server1.theirhost.com/~acct/somewebsite.com/wordpress/wp-admin/admin-ajax.php

When doing ajax requests from a page on http://www.somewebsite.com, it looks like the “same origin policy” is in effect and the requests fail. Any suggestions on how to fix this issue?

Depending on how you’re mapping somewebsite.com, you can probably just define ajaxurl differently:

var ajaxurl="http://www.somewebsite.com/admin-ajax.php";

If you need something more generalizable, you could filter admin_url, sniff out whether it’s asking for admin-ajax.php, and if so, then rewrite it using home_url() or something like that.

Getting cross-domain ajax to work is possible (with a proxy approach, for instance) but it’s best to avoid it if at all possible.