How to declare a variable in php while including files?

So i have three files.

FILE 1 includes FILE 2 which includes FILE 3

FILE 1 needs to print VAR 1 which is defined in FILE 3

how would I do that? Its not echoing out for me

file 1

<?php
if ($_GET["pg"]==false)
echo "<title>Socal Mo开发者_开发知识库ds</title>";
else
echo $title_name;
?>

file 2

<?php 
if ($_GET["pg"]==false)
include("home.php");
else
include("".$_GET["pg"].".php");
?>

file 3

<?php $title_name="<title>Socal Mods</title>" ?>

file 3 is being parsed into file 1 which is the display container, but the %title_name is not echoing

One thing first about how you access the GET variables. You check the value using $_GET["pg"] == false. Note that this expression will fail to do what you expect in a lot situations. In fact, the value will never be directly false. The only way it will equal to false if it is empty or unset (in which case you will also get a compiler warning, which you should avoid). Usually a safer way to check if the value was set is using isset( $_GET["pg"] ).

The next thing I want to address is a security problem you introduce. You use the GET value directly to include a file with that name. If I was a user with malicious intent, I could easily set the pg value to something, you usually wouldn't expect and which break your website in some way. You generally should avoid using data the user entered somehow (request parameters are user data), and make sure to sanitize them first. A good way to do this, when you plan to use the value as a base to which page you want to include, would be to have some kind of whitelist of acceptable/allowed values. Then you can check if the entered data is in that whitelist and if that is the case, include the correct page. Another simple way would be using a switch statement to simply go through all accepted cases.

Now finally, onto your problem: I'm not sure if this was just a mistake when you posted the code, but file 1 is missing the include of file 2. As such you will never include file 3, and of course the variable will never be set.

Another problem might be the usage of the GET value. If the value does not contain the exact filename (as in casing and no extra whitespace), then the file won't be found. It is a good idea to echo out the filename you want to include in file 2, just to check if you are making any mistakes. The whitelist as explained above would be another way to make sure that you are trying to include the correct file.

Finally, you should enable error reporting on your server, you can do that either in your server configuration, or by adding the following line to the top of your first file (i.e. file 1):

error_reporting( E_ALL );

That way you will get errors and warnings that will tell you if something unexpected happened at runtime, and you might see your mistake easier.

Old answer

In general it works like this:

File 1:

 <?php
 include 'file2.php';
 echo $myVariable; // prints 'Hello World!'
 ?>

File 2:

 <?php
 include 'file3.php';
 ?>

File 3:

 <?php
 $myVariable = 'Hello World!';
 ?>

echo    $title_name = "<title>Socal Mods</title>";

It means its echoing html, So "Socal Mods" will be seen in title bar instead of the body. I hope you are looking in the titlebar. And to use $title_name in file 1 which is available in file 3 you hv to include file3 in file1.

Is file 3 included in the script? And have you actually validated and confirmed that the file is included? If you change the include statements in your script into require statements, PHP will stop with an error if the file you are looking for does not exist.

There are many reasons why a file might not be found. If the file name contains uppercase letters and the request only contains lowercase letters, you will run into problems if the server uses a case sensitive file system.

Also you should sanitize user input before you use that to include files. You don't want me to be able to include any file anywhere on your server, do you?

Variabes have to be created, set and assigned a value before they can be echoed.

Most probably ( please show us some code ), your problem is not the file includes, but you are trying to echo your variable before it is assigned a value.