When the PHP code is generated on the server and sent to the client, is the resulting PHP code visible?
I want to create a registration code using the PayPal IPN, but I don't want the algorithm to be visible, nor do I want any of the PHP code (or it's derivative) to be visible.
Correct, the PHP code will be parsed by the server and only the generated HTML code is send to the client. Ofcourse this HTML code is visible in the source, but not the PHP you used. Just try it and look at the sourcecode.