提交表单到另一个域

I need to access the result of submitting a form to a website.

There is a web site where you complete a form and it posts the information using ajax and then tells you if you have their service in the are or not.

I'd like to be able to do this from my web page, which means posting the information required by the form to their server and getting the result.

The problem is I get "403 Forbidden", I think it's because the "Origin" being a different domain.

Is there anyway that I can the response from the server on my website? I thought about php_curl (used once with google docs api) but would like to know what you guys think it's the best way.

Proxying the request through your own web server that is available in the same domain as the webpage making the ajax call is the only clean way.