Securing a remote ajax method call

Question

I have coded some JavaScript to perform an ajax call in an asp.net application. This triggers a method that calls a URL, sending some parameters in the POST.

The rec

Answer 1

Are all your customers on your domain?
If not you won't be able to use the XMLHttpRequest object to send data from their site. The XHR is subject to the Same Origin Policy.
You may be able to post to a page from your server in an iframe. You would need to prompt your users for their username and password so that these details aren't exposed your script and the target should be served over ssl.