So I had this trouble with a PHP code that I solved, but I don't really know how it works.
I tried to add this to every single file
<?php include '/nav.php'; ?>
So I can only have one file to edit the navbar instead of the whole php files.
The problem came up when I added that code to the files of another folder (ie. /general/vision.php) and I got an error (file not found). I though it was because I only hav the 'nav.php' file on the root of the site.
So, just for fun, I changed the sentence of the /general/vision.php file to
<?php include '../nav.php'; ?>
And it worked. I didn't changed the nav.php from the root, and it worked.
I'm glad it did, but I don't know why. How does that /../ works? Is that listed on the PHP documentation?
..
is OS nomenclature for "up a directory." It's nothing PHP specific.
Take a look at the concept of Relative paths.. might shed some light. Relative paths vs Absolute paths.