WordPress.org

In jQuery 1.5+ (bundled with WordPress 3.2+), AJAX requests on sites with IDN domains don't work in IE or Opera.

On Edit Post screen, adding a new category results in JS error:

Message: 'parsed.responses' - is null or not an object

On Categories screen, adding a new category silently fails.

According to jaubourg's comment in jQuery bug tracker, the request is considered cross-domain and, since IE doesn't support cross-domain requests, AJAX won't find a suitable transport and bail out.

This plugin implements a workaround suggested there by making AJAX requests relative.

WordPress Trac ticket: #18952