Are
you getting sick of typing the same things over and over again? The makers of
PHP have blessed us frustrated developers with a little time-saving device
called “includes” that save you from reentering frequently used text over and
over. Suppose that you want to type the same message on every page of your
site. Perhaps it is your company’s
name
and address, or maybe today’s date. If you are coding each page of your site
from scratch, this is not very efficient for a couple of reasons:
❑ You are typing the same
information over and over again, which is never good.
❑ In the case of an update
or a change, you have to make the change in every single page of your site.
Again, this is redundant and time consuming, and it elevates the potential for
human error.
A
solution to this problem is to use an include. Includes are PHP files tucked
into other PHP files. You take commonly used information and put it in a
separate file. For example, if you have a set of defined variables that need to
be referenced in every page on your site, you could define them once, in a
single PHP script. Then, on each of your pages where you want the variables to
appear, you use an include statement that specifies the file that defines the
variables. When your script is parsed, the parser inserts the code from the
include file into your page, just as if you’d typed it there yourself. The final
output is then sent to the browser. Includes can use any extension, but are
sometimes referenced as .inc files. If you are adding potentially sensitive
information, for example, server variables such as passwords, then it is
advisable to save these in .php files so they are never accessible to anyone
because the information is parsed before it is sent to the browser. You can add
an include in any other file, and if you place the include statement in an if statement,
you can control when the include is inserted.
Try It Out Adding a Welcome Message
Suppose
you want every page in the movie review site to show a welcome message and
perhaps today’s date. You want to create a file that includes this information,
so follow these steps:
1.
Open your text editor and type the following:
<div align=”center”><font size=”4”>Welcome to my
movie review site!</font>
<br>
<?php
echo “Today is “;
echo date(“F d”);
echo “, “;
echo date(“Y”);
?>
</div>
2.
Save this file as header.php.
3. To
include this file in the three existing movie Web site files, add the following
line immediately after the <body> tag
to login.php :
<?php include “header.php”; ?>
4.
Save your files.
5.
Take a look at the files again. If you open login.php and You will see the same two lines on every
page where you have included the header.php file.
No comments:
Post a Comment