By Stephon Unomon
A PHP include is used when you want
to include the contents of one file inside another...a very useful command!
<?php
include("file.inc");
?>
Real World Usage for
Includes
Let’s say you are developing a 5 page
website that you might be adding pages to. Your navigation HTML looks like
this:
<html>
<head>
<title>My
Navigation</title>
</head>
<body>
</body>
</html>
...and this is going to be in every page. Now, when you add
a page to your website, you are going to have to change the code on all 5 pages
to reflect the new link. This could take several minutes to do...and what if
the site expands to 20 pages or more? It’s going to be a nightmare!
PHP Includes to the rescue!
Turn the page and watch PHP save our developer from certain
doom!
Let’s cut the
menu link code out of the example above and paste it into a new plain text
document (You can use Notepad on Windows or TextEdit on the Mac for this).
Save this text
file as navigation.inc. Paste the following in place of where the code was in
the original HTML files...
<?php
include
"navigation.inc" ;
?>
Then save the
HTML page as a PHP page. Voila! Any time you need to change the menu links, all
you have to do is edit one file - the navigation.inc file!
I Require You To
Include
In PHP, you can also use the “Require” command in place of
Include. The major difference between the two is that using Require will stop
the script from running (the page won’t load completely) if it cannot find the
page that is referenced for inclusion. An Include will allow the page to load,
but it will just ignore the included code if it cannot be found.
Now let’s mesh it all
together in an example!
Imagine
this...you are building a website. Your Greatest Undertaking Of A Website. 200
Pages. 400 Articles. Writing Code By Hand. The Titan Of Websites. You want to
put advertising on each page (We’ll use GoogleTM AdSense as an
example). You also want to test different color themes on the ad code, or
change the ads periodically. You are also going to be quite generous and give
copies of this website away for others to use.
The questions
start filling your mind...how can I easily change the ad colors or format? How
can I let other people easily put in their AdSense publisher code?
We’ll use Variables and Includes to solve the problem!
Open up 2 blank text documents. The first one is going to be
a settings file, the second one is going to be your Ad code.
In the settings file, you are going to want to set variables
for things you know you are going to want to change, the main thing being the
AdSense publisher code and the ad link colors. So, we’ll set the variables as
below...
<?php
$ad_pub_num = “pub-0123456789”;
$eb_linkcolor = “006699”;
?>
The variable, $ad_pub_num, now reflects the AdSense
publisher tracking code, and the link colors are the HTML color code 006699,
which is a dark blue. Save this page as settings.php.
Now, grab your AdSense code snippet from Google...
<script
type="text/javascript"><!--
google_ad_client
= "pub-0123456789";
google_ad_width
= 120;
google_ad_height
= 600;
google_ad_format
= "120x600_as";
google_ad_type
= "text_image";
google_ad_channel
= "1";
google_color_border
= "FFFFFF";
google_color_bg
= "FFFFFF";
google_color_link
= "006699";
google_color_text
= "006699";
google_color_url
= "006699";
//--></script>
<script type="text/javascript"
</script>
And paste it into the other open document...making some
changes...
<?php
echo "
<script
type=\"text/javascript\"><!--
google_ad_client
= \"$ad_pub_num\";
google_ad_width
= 120;
google_ad_height
= 600;
google_ad_format
= \"120x600_as\";
google_ad_type
= \"text_image\";
google_ad_channel
= \"1\";
google_color_border
= \"FFFFFF\";
google_color_bg
= \"FFFFFF\";
google_color_link
= \"$eb_linkcolor\";
google_color_text
= \"$eb_linkcolor\";
google_color_url
= \"$eb_linkcolor\";
//--></script>
<script type=\"text/javascript\"
</script>
?>
...and save this file as ads.php.
Do you recognize the changes we made? We’ve told PHP to echo
the code to the screen, and put in the variables that we set in the
settings.php file. Since we are doing an ECHO, we’re displaying the quotation
marks in the output with the \” code (That’s the way the AdSense snippet
works). Now we are ready to call these files from the main web pages!
At the beginning of your content pages, you will want to add
this code:
<?php
require “settings.php”;
?>
This tells the page that it requires the contents of
Settings.php file to be included. Including this code on each page sets the
variables we will use throughout the site.
Now, call the ads in the places you want them:
<?php
include “ads.php”;
?>
This will pull in the code from the ads page we made,
including the variables we set, and show those ads wherever you care to place
them. So, your ad link colors will appear in a dark blue and the example
publisher number - pub-0123456789 - will show up in the ads. Name each one of
your content pages as .php instead of .html, and you’ll be good to go! If you
decide you want to change colors of the ads (or change the AdSense publisher ID
code), you only have to make that change in ONE file instead of 200 - the
settings.php file!
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