is it possible to communicate with another domain javascript function using ajax

[pankaj.ghadge]

hello,

Is it possible to communicate with another domain javascript function using ajax.
Suppose i have a iframe and domain is different and in the iframe i have some links. If user clicks on that link i want to call javascript function written in main page (not in iframe). is this possible using ajax to call the java script function of another domain.
if possible please tell me the example.
if not please tell me the another way.

please help me out...............

Thanks in advance.

check out this
http://www.julienlecomte.net/blogfiles/cross-frame/
what are these API for cross domain communication please tell me it is secure or not
if it is secure how to use this API please tell me