Home
>
Software
>
PHP On-The-Fly!

PHP On-The-Fly!

Introduction

PHP can be used for a lot of different things, and is one of the most powerful scripting languages available on the web. Not to mention it's extremely cheap and widely used. However, one thing that PHP is lacking, and in fact most scripting languages are, is a way to update pages in real-time, without having to reload a page or submit a form.

The internet wasn't made for this. The web browser closes the connection with the web server as soon as it has received all the data. This means that after this no more data can be exchanged. What if you want to do an update though? If you're building a PHP application (e.g. a high-quality content management system), then it'd be ideal if it worked almost like a native Windows/Linux application.

But that requires real-time updates. Something that isn't possible, or so you would think. A good example of an application that works in (almost) real-time is Google's GMail (http://gmail.google.com). Everything is JavaScript powered, and it's very powerful and dynamic. In fact, this is one of the biggest selling-points of GMail. What if you could have this in your own PHP websites as well? Guess what, I'm going to show you in this article.

How does it work?

If you want to execute a PHP script, you need to reload a page, submit a form, or something similar. Basically, a new connection to the server needs to be opened, and this means that the browser goes to a new page, losing the previous page. For a long while now, web developers have been using tricks to get around this, like using a 1x1 iframe, where a new PHP page is loaded, but this is far from ideal.

Now, there is a new way of executing a PHP script without having to reload the page. The basis behind this new way is a JavaScript component called the XML HTTP Request Object. See http://gmail.google.com for more information about the component. It is supported in all major browsers (Internet Explorer 5.5+, Safari, Mozilla/Firefox and Opera 7.6+).

With this object and some custom JavaScript functions, you can create some rather impressive PHP applications. Let's look at a first example, which dynamically updates the date/time.

Example 1

First, copy the code below and save it in a file called 'script.js':

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 = 'Loading ...';

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':

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.

Example 1

function updatedate() {

loadFragmentInToElement('http://www.yourdomain.com/server1.php', 'currentdate');

}

The current date is .

Now go to http://gmail.google.com 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://gmail.google.com

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':

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.

Example 2

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);

}

U se the below form to add up two numbers. The answer is calculated by a PHP script, and not with JavaScript. What's the advantage to this? You can execute server-side scripts (PHP) without having to refresh the page.

+ =

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://gmail.google.com 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 (http://gmail.google.com) 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.

About The Author

Dennis Pallett is a young tech writer, with much experience in ASP, PHP and other web technologies. He enjoys writing, and has written several articles and tutorials. To find more of his work, look at his websites at http://gmail.google.com http://gmail.google.com and http://gmail.google.com

http://gmail.google.com

Wood Dale Chicago prom limo .. Lockport Chicago limo O’Hare

In The News:

Fueled by artificial intelligence, CyberDog the robotic dog is designed specifically locate fire ant nests, which are endangering ecosystems.

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents

Internet browsers are useful, but they can be dangerous. Clicking on malicious links can direct you to dangerous websites that steal information or infect your device.

Apple's latest iOS update introduces advanced artificial intelligence capabilities, which may be capturing and analyzing sensitive information.

Breach site confirmed 56,904,909 Hot Topic users' data leaked online. Tech expert Kurt “CyberGuy" Knutsson says the company's silence makes matters even worse.

Tech expert Kurt “CyberGuy" Knutsson discusses how an innovative Easy-Way kit turns standard strollers electric, simplifying navigation for parents.

Tech expert Kurt “CyberGuy" Knutsson talks about T-Mobile being hacked in broad cyberattack on global phone and internet companies.

Tech expert Kurt “CyberGuy" Knutsson shows you how to add, customize and manage widgets for quick access to apps and info from your iPhone home screen.

Wrong Google searches can not only compromise your device and personal data. They can also bring law enforcement to your doorstep. Hackers are targeting Google searches.

China's Shanghai Kepler Robotics has developed a new humanoid robot that can carry up to 35 pounds per hand for commercial applications across various industries

Checking your hearing has gotten easier with the new hearing test feature in AirPods Pro 2. You can take reliable hearing tests using your iPhone or iPad.

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.

Kurt "CyberGuy" Knutsson explains how a VPN — virtual private network — works and how running it can slow down the operation of your device.

The WalkON Suit F1, an exoskeleton developed to help people with disabilities, can actually walk over to a person in a wheelchair, solving a major problem.

ClickFix, a new scam targeting computer users, is on the rise in the U.S. The scam prompts its targets to click on a link to fix a problem.

Skydweller is the world's largest unmanned solar-powered aircraft that can stay airborne for weeks, and even months, without refueling.

The U.S. government said it is investigating after People's Republic of China hackers targeted commercial telecommunications service providers in the U.S.

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.

Scammers are using increasingly sophisticated ways to lure unsuspecting victims, and some are impersonating an email help desk or support team.

You can unsend or edit your iMessages with the latest iOS updates. Kurt the CyberGuy explains how you can save yourself some potential embarrassment.

Kurt “CyberGuy" Knutsson says there’s been a rise in cybercriminal services using hacked police and government emails to send subpoenas and data requests to U.S. companies.

Kurt “CyberGuy" Knutsson discusses how Axiom Space and luxury designer Prada are collaborating on NASA's Artemis III spacesuit design.

Voice assistants may cause confusion across devices. Tech expert Kurt “CyberGuy" Knutsson offers some solutions to fix it.

Shameless scammers trick veterans into giving personal info or cash. Tech expert Kurt “CyberGuy" Knutsson explores five common scams.

PHP On-The-Fly!

Software