Question

I’ve been working on a project on my local server. The time has come to upload it so I did just that. I started to test it out online and my navigation isn’t working.

The navigation works by doing this:

<a href="index.php?p=add">Add</a>

The page then checks whether $p exists and if it does, it shows the relevant content. For some reason though my content isn’t showing up when I click the links. I turned on error reporting, and I added this (line 39)

echo $p;

to the document. Now I get this error: Notice: Undefined variable: p in /home/silver/public_html/admin/index.php on line 39 but only when testing online and it works fine when I test it locally.

I can post my code if I need to, but there’s a lot of it and I’m not sure which bit is the problem.

UPDATE:
Thanks for all the replies, but I’m confused as to how you use your suggestions as I’m used to doing things the way I was.

At the moment, I do this to check what the $p variable is

<?php if(!isset($p)) { // DEFAULT PAGE VIEWED AT INDEX.PHP ?>

And use this to link to the page:

<a href="index.php?p=add">Add New Item</a>

Answer 1

You’re relying upon register_globals, an outdated and deprecated feature of PHP. This feature automatically translates GET, POST, COOKIE, SERVER etc. variables and inserts them into the global scope. This means that file.php?p=blah would result in $p == 'blah'. This is a bad idea for lots of different scoping and security reasons outlined in the PHP manual.

Use the superglobals (e.g. $_GET, $_POST, $_SERVER) instead.

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In response to your updated question, your code

<?php if(!isset($p)) { // DEFAULT PAGE VIEWED AT INDEX.PHP ?>

should become

<?php if(!isset($_GET['p'])) { // DEFAULT PAGE VIEWED AT INDEX.PHP ?>