Calling PHP functions from different domains

[hektor22]

Is it possible to call a PHP function found in a file on another website with a different domain? For example, I know that to call a PHP function from another file in the same domain (say function aaa() found in aaa.php) I just have to simply do this (with a few simplifying assumptions):\[code\]include_once('aaa.php');aaa();\[/code\]I have tried doing something similar, such as:\[code\]include_once('http://othersite/aaa.php');aaa();\[/code\]I cannot get this to work (the page seems to load fine, with no error messages, but the function does not execute). I have tried require(), which gives me a blank screen. I have had no success with fopen either.If it is possible to do this, how can I do it?