PHP - include Function

I hope you are enjoying this interesting series. Today we are going to learn about Include function. You can insert the content of a file into a 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. The include() function generates a warning (but the script will continue execution) while the require() function generates a fatal error (and the script execution will stop after the error).

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

This can save the developer a considerable amount of time. This means that you can create a standard header or menu file that you want all your web pages to include. When the header needs to be updated, you can only update this one include file, or when you add a new page to your site, you can simply change the menu file (instead of updating the links on all web pages).

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.

Example 1

Assume that you have a standard header file, called “header.php”. To include the header file in a page, use the include() function, like this:

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

Example 2

Now, let’s assume we have a standard menu file that should be used on all pages (include files usually have a “.php” extension). Look at the “menu.php” file below:

<html>
<body>
 
<a href="http://www.heygb.com/default.php">Home</a> |
<a href="http://www.heygb.com/about.php">About Us</a> | 
<a href="http://www.heygb.com/contact.php">Contact Us</a>

The three files, “default.php”, “about.php”, and “contact.php” should all include the “menu.php” file. Here is the code in “default.php”:

<?php include("menu.php"); ?>
 
<h1>Welcome to my home page</h1>
 
<p>Some text</p>
 
</body>
</html>

If you look at the source code of the “default.php” in a browser, it will look something like this:

<html>
<body>
	<a href="default.php">Home</a> |
	<a href="about.php">About Us</a> | 
	<a href="contact.php">Contact Us</a>
	<h1>Welcome to my home page</h1>
	<p>Some text</p>
</body>
</html>

And, of course, we would have to do the same thing for “about.php” and “contact.php”. By using include files, you simply have to update the text in the “menu.php” file if you decide to rename or change the order of the links or add another web page to the site.



Pages : 1 2