PHP On-The-Fly!
var xmlhttp=false; /*@cc_on @*/
/*@if (@_jscript_version >= 5) // JScript gives us
Conditional compilation, we can cope with old IE versions. //
and security blocked creation of the objects. try { xmlhttp =
new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try
{ xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); }
catch (E) { xmlhttp = false; } } @end @*/ if (!xmlhttp
&& typeof XMLHttpRequest!='undefined') { xmlhttp = new
XMLHttpRequest(); }
function loadFragmentInToElement(fragment_url, element_id) { var
element = document.getElementById(element_id); element.innerHTML
= '<em>Loading ...</em>';
xmlhttp.open("GET", fragment_url);
xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState
== 4 && xmlhttp.status == 200) { element.innerHTML =
xmlhttp.responseText; } } xmlhttp.send(null); } Then copy
the code below, and paste it in a file called 'server1.php':
<?php echo date("l dS of F Y h:i:s A"); ?>
And finally, copy the code below, and paste it in a file
called 'client1.php'. Please note though that you need to edit
the line that says 'http://www.yourdomain.com/server1.php' to
the correct location of server1.php on your server.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01
Strict//EN"> <html> <head>
<title>Example 1</title> <script
src="script.js"
type="text/javascript"></script>
<script type="text/javascript"> function
updatedate() {
loadFragmentInToElement('http://www.yourdomain.com/server1.php',
'currentdate'); }
</script> </head>
<body> The current date is<span
id="currentdate"><?php echo date("l dS of F
Y h:i:s A"); ?></span>.<br /><br />
<input type="button" value="Update date"
OnClick="updatedate();" /> </body>
</html> Now go to
http://www.yourdomain.com/client1.php and click on the button
that says 'Update date'. The date will update, without the page
having to be reloaded. This is done with the XML HTTP Request
object. This example can also be viewed online at http://www.phpit.net/demo/php%20on%20the%20fly/client1.php.
Example 2 Let's try a more advanced example. In the
following example, the visitor can enter two numbers, and they
are added up by PHP (and not by JavaScript). This shows the true
power of PHP and the XML HTTP Request Object.
This example uses the same script.js as in the first example, so
you don't need to create this again. First, copy the code below
and paste it in a file called 'server2.php': <?php // Get numbers $num1 = intval($_GET['num1']); $num2 = intval($_GET['num2']); // Return answer echo ($num1 + $num2); ?>And then, copy the code below, and paste it in a file called 'client2.php'. Please note though that you need to edit the line that says 'http://www.yourdomain.com/server2.php' to the correct location of server2.php on your server.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01
Strict//EN"> <html> <head>
<title>Example 2</title> <script
src="script.js"
type="text/javascript"></script>
<script type="text/javascript"> function calc()
{ num1 = document.getElementById ('num1').value; num2 =
document.getElementById ('num2').value;
var element = document.getElementById('answer');
xmlhttp.open("GET",
'http://www.yourdomain.com/server2.php?num1=' + num1 +
'&num2=' + num2); xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
element.value = xmlhttp.responseText; } } xmlhttp.send(null); }
</script> </head>
<body> Use the below form to add up two numbers. The
answer is calculated by a PHP script, and
<em>not</em> with JavaScript. What's the advantage
to this? You can execute server-side scripts (PHP) without
having to refresh the page.<br /><br />
<input type="text" id="num1"
size="3" /> + <input type="text"
id="num2" size="3" /> = <input
type="text" id="answer" size="5"
/>
<input type="button" value="Calculate!"
OnClick="calc();" /> </body>
</html> When you run this example, you can add up
two numbers, using PHP and no reloading at all! If you can't get
this example to work, then have a look on http://www.phpit.net/demo/php%20on%20the%20fly/client3.php
to see the example online.
Any Disadvantages...? There are only two real
disadvantages to this system. First of all, anyone who has
JavaScript turned off, or their browser doesn't support the XML
HTTP Request Object will not be able to run it. This means you
will have to make sure that there is a non-JavaScript version,
or make sure all your visitors have JavaScript enabled (e.g. an
Intranet application, where you can require JS).
Another disadvantage is the fact that it breaks bookmarks.
People won't be able to bookmark your pages, if there is any
dynamic content in there. But if you're creating a PHP
application (and not a PHP website), then bookmarks are probably
not very useful anyway.
Conclusion As I've shown you, using two very simple
examples, it is entirely possible to execute PHP scripts,
without having to refresh the page. I suggest you read more
about the XML HTTP
Request Object and its capabilities.
The things you can do are limitless. For example, you could
create an extremely neat paging system, that doesn't require
reloading at all. Or you could create a GUI for your PHP
application, which behaves exactly like Windows XP. Just think
about it!
Be aware though that JavaScript must be enabled for this to
work. Without JavaScript this will be completely useless. So
make sure your visitors support JavaScript, or create a
non-JavaScript version as well.
Category: CGI