For some reason I can't get the page that runs the phpinfo() function up. I get an HTTP 404 Not found message brought up. Its in the www folder, the same folder as my testing.html, with this exact code written for it:

<?php
phpinfo();
?>

It doesn't want to come up. Any reasons why?

404 Error means server can not find the script you enter in the browser URL. Double check your script name again.

Make sure you name your script ending in .php , not .html

I had a problem with the same function so I thought it's good to ask here for a solution, my problem is that when I opened the ( testing.php ) it installed on my computer, instead of show as a webpage,
The book says that " PHP is not installed or Apache does not know about the PHP module."
- how can that happend and I installed the php, apache, and MySql together in MAMP.

plz need a solution quickly I wanna start learning.
thank you.

I suggest you ask on MAMP forum since it is the source of the problem.

http://forum.mamp.info/viewforum.php?f=6

Specific your OS version, MAMP version and screenshot if applicable. People are willing to help if everything is there for them to debug.

thank you, I went to the MAMP forum, but really I got confused, and I got no answer or maybe they did not publish my post.
but I searched in youtube and I got my the point.
the problem was in the post so I changed the Apache and MySql ports form 8888 for both to the default Apache and MySql ports.