PHP File
Inclusion
You can include the content of a PHP file into
another PHP file before the server executes it. There are two PHP functions
which can be used to included one PHP file into
another PHP file.
This is a strong point of PHP which helps in
creating functions, headers, footers, or elements that can be reused on
multiple pages. This will help developers to make it easy to change the layout
of complete website with minimal effort. If there is any change required then
instead of changing thousand of files just change
included file.
The include()
Function
The
include() function takes all the text in a specified
file and copies it into the file that uses the include function. If there is
any problem in loading a file then the include() function generates a warning
but the script will continue execution.
Assume you want to create a common menu for your
website. Then create a file menu.php with the
following content.
<a href="http://www.example.com/index.htm">Home</a> -
<a href="http://www. example.com/ebxml">ebXML</a> -
<a href="http://www. example.com/ajax">AJAX</a> -
<a href="http://www. example.com/perl">PERL</a> <br />
Now create as many pages as you like and include
this file to create header. For example now your test.php
file can have following content.
<html>
<body>
<?php include("menu.php"); ?>
<p>This is an example to show how to include PHP file!</p>
</body>
</html>
It will produce the following result −
The require() Function
The require() function
takes all the text in a specified file and copies it into the file that uses
the include function. If there is any problem in loading a file then the require() function
generates a fatal error and halt the execution of the script.
So there is no difference in require()
and include() except they handle error conditions. It is recommended to use the
require() function instead of include(), because
scripts should not continue executing if files are missing or misnamed.
You can try using above example with require() function and it will generate same result. But if
you will try following two examples where file does not exist then you will get
different results.
<html>
<body>
<?php include("xxmenu.php"); ?>
<p>This is an example to show how to include wrong PHP file!</p>
</body>
</html>
This will produce the following result –
Home -
ebXML -
AJAX -
PERL
This
is an example to show how to include PHP file!
This is
an example to show how to include wrong PHP file!
Now lets try same example
with require() function.
<html>
<body>
<?php require("xxmenu.php"); ?>
<p>This is an example to show how to include wrong PHP file!</p>
</body>
</html>
This time file execution halts and nothing is
displayed.
NOTE −
You may get plain warning messages or fatal error
messages or nothing at all. This depends on your PHP Server configuration.