Include another PHP files

You can insert the content of one PHP file into another PHP file before the server executes it, with the include() or require() function.

The two functions are identical in every way, except how they handle errors:

• include() generates a warning, but the script will continue execution
• require() generates a fatal error, and the script will stop

These two functions are used to create functions, headers, footers, or elements that will be reused on multiple pages.

Include 
<?php include("header.php"); ?>
<h1>Welcome to my home page!</h1>
<p>Some text.</p>

<div class="leftmenu">
<?php include("menu.php"); ?>
</div>

<h1>Welcome to my home page.</h1>
<p>Some text.</p>

Require

<?php
require("wrongFile.php");
echo "Hello World!";
?>

Include Vs. Require

In include : Notice that the echo statement is executed! This is because a Warning does not stop the script execution
-------------------------------------

Warning: include(wrongFile.php) [function.include]:
failed to open stream:
No such file or directory in C:\home\website\test.php on line 5

Warning: include() [function.include]:
Failed opening 'wrongFile.php' for inclusion
(include_path='.;C:\php5\pear')
in C:\home\website\test.php on line 5

Hello World!

-------------------------------------

In Require : The echo statement is not executed, because the script execution stopped after the fatal error.

-------------------------------------

Warning: require(wrongFile.php) [function.require]:
failed to open stream:
No such file or directory in C:\home\website\test.php on line 5

Fatal error: require() [function.require]:
Failed opening required 'wrongFile.php'
(include_path='.;C:\php5\pear')
in C:\home\website\test.php on line 5

-------------------------------------