Say we wanted to create a common menu file that
all our pages will use. A common practice for naming files that are to
be included is to use the ".php" extension. Since we want to create a
common menu let's save it as "menu.php".
PHP Include
Without understanding much about the details of PHP, you can save yourself a great deal of time with the use of the PHP include command. include takes a file name and simply inserts that file's contents into the script that issued the include command.
Why is this a cool thing? Well, first of all, this means that you
can type up a common header or menu file that you want all your web
pages to include. When you add a new page to your site, instead of
having to update the links on several web pages, you can simply change
the Menu file.
An Include Example
Say we wanted to create a common menu file that all our pages
will use. A common practice for naming files that are to be included is
to use the ".php" extension. Since we want to create a common menu
let's save it as "menu.php".
menu.php Code:
<html>
<body>
<a href="http://www.example.com/index.php">Home</a> -
<a href="http://www.example.com/about.php">About Us</a> -
<a href="http://www.example.com/links.php">Links</a> -
<a href="http://www.example.com/contact.php">Contact Us</a> <br />
Save the above file as "menu.php". Now create a new file, "index.php" in the same directory as
"menu.php". Here we will take advantage of the include command to add our common menu.
index.php Code:
<?php include("menu.php"); ?>
<p>This is my home page that uses a common menu to save me time when I add
new pages to my website!</p>
</body>
</html>
Display:
This is my home page that uses a common menu to save me time when I add new pages to my website!
And we would do the same thing for "about.php", "links.php", and "contact.php". Just think
how terrible it would be if you had 15 or more pages with a common menu and you decided to add
another web page to that site. You would have to go in and manually edit every single file to add this
new page, but with include files you simply have to change "menu.php" and all your problems are solved.
Avoid such troublesome occasions with a simple include file.
What do Visitors See?
If we were to use the include command to insert a menu on each of our web pages, what
would the visitor see if they viewed the source of "index.php"? Well, because the include command
is pretty much the same as copying and pasting, the visitors would see:
View Source of index.php to a Visitor:
<html>
<body>
<a href="index.php">Home</a> -
<a href="about.php">About Us</a> -
<a href="links.php">Links</a> -
<a href="contact.php">Contact Us</a> <br />
<p>This is my home page that uses a common menu to save me time when I add
new pages to my website!</p>
</body>
</html>
The visitor would actually see all the HTML code as one long line of
HTML code, because
we have not inserted any new line characters. We did some formatting
above to make it easier to read. We will be discussing new line
characters later.
Include Recap
The include command simply takes all the text that exists in the
specified file and copies
it into the file that uses the include command. Include is quite useful
when you want to include the same PHP, HTML, or text segment on
multiple pages of a website. The include command is used widely by PHP
web developers. Like PHP Echo, include is not a function, but a language construct.
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