How to I inject only certain parts of PHP page using PHP

[proobioks]

I'm a total beginner when it comes to PHP, so bare with me. I know I can include other files using PHP\[code\]<?php include("file.php"); ?>\[/code\]Now my question is how do I inject only certain parts of "file.php"?Lets say I have some header code and some footer code within file.php. How do I organize file.php with the correct separated section, and how do only include certain sections of the file.php (\[code\]file.php?footer\[/code\] or something like that?)