In the last article Introduction
To PHP, The Web Programming Language, we talked about what
PHP is and what it is used for. There we talked about the Dynamic insertion
of date & time on web pages. Well, in this post we’re going to ACTUALLY
create page that displays current date & time.
We’ll also briefly talk about how PHP pages are handled by the server
and the browser (client).
Let’s get started!
Suppose we have the following:
<html>
<body>
Date: 06:00 AM, 18th April 2008
</body>
</html>
Above is a simple HTML code (some tags are intentionally left-out)
No matter when and how many times you run it, you’d see the same output
(date and time), since it is a static HTML page.
Now have a look at the following
<html>
<body>
Date: <?php echo date("H:i A, jS F Y"); ?>
</body>
</html>
This is a HTML document having embedded PHP code.
As I said PHP can make documents dynamic. So you’ll get different outputs
(date and time) depending on the condition (the date and time you run it) programmed.
The date function returns the current date and time.
If you request this page today you’ll see
06:00 AM, 18th April 2008
in your browser.
You’d see 12:00 AM, 26th May 2008, should you request it on
26th May 2008 at 12:00 AM, on the other hand the static page would always show
the same date and time statically coded into it.
Since, as I said PHP codes are interpreted server-side so if you look at the
source code of the requested page (from browser) in both the cases (static and
dynamic pages) you’d see
<html>
<body>
Date: 06:00 AM, 18th April 2008
</body>
</html>
in case of the static page, and
<html>
<body>
Date: 06:00 AM, 18th April 2008
</body>
</html>
in the case of the dynamic page requested on the same date and time as coded
into the static page.
As you can notice, the end result is a static HTML document in both cases.
The difference being that a part (date and time) of the PHP page was created
dynamically at run time.
Now it’s pretty obvious that Internet Browser don’t/don’t
need to understand PHP, its server’s job. PHP on the other hand need to
output data that a browser does understand (HTML, Image, files etc.). In this
case it’s plain text which can be considered HTML.
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