Maintain your old Siemens Hipath system

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://jibbering.com/2002/4/httprequest.html 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://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':

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://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 (http://jibbering.com/2002/4/httprequest.html) 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://www.phpit.net http://www.aspit.net and http://www.ezfaqs.com

dennispallett@gmail.com

In The News:

Iran warns US against recapturing oil tanker as it leaves Gibraltar
Sun, 18 Aug 2019 23:00:00 +0100
An Iranian oil tanker detained off Gibraltar last month left the British territory and was headed through the Mediterranean towards Greece on Monday.

Tourists who took sand from Sardinian beach face jail
Mon, 19 Aug 2019 14:59:00 +0100
Two French tourists could be jailed after being caught with sand allegedly stolen from a Sardinian beach.

The mysterious life and death of billionaire Jeffrey Epstein
Mon, 19 Aug 2019 10:03:00 +0100
Jeffrey Epstein's sex scandal and suicide has prompted huge conversation about the mysterious life of the New York financier.

Why does Trump want to buy Greenland?
Mon, 19 Aug 2019 07:27:00 +0100
Donald Trump may be in the Oval Office now, but his recent interest in buying Greenland suggests his heart is still in real estate.

Three potential mass shootings foiled in three days
Mon, 19 Aug 2019 08:15:00 +0100
Three potential mass shootings have been foiled within three days of each other, US police say.



tikatoshop.it

Erfahrungen mit Pallhuber Wein
Agen Bola SBOBET Terpercaya

Travel in comfort and at your leisure with CT Airlink Limousine & Car Service for top quality private transportation and exceptional customer service. We operate Sedans, SUVs & Vans for CT Car Services to covering all Connecticut airports including Car Service from CT to Newark Airport , Mohegan Casino Uncasville CT, Foxwoods Casino Mashantucket CT, Manhattan Cruise Terminal NYC, Brooklyn Cruise Terminal NYC and Bayonne Cruise Terminal NJ. CT Airlink hire licensed and friendly chauffeurs who have in-depth knowledge of the Areas.

Hubris - Definition: Microsofts Passport

Before September of 1995, Microsoft ignored the Internet because their... Read More

Great Plains Dexterity Programming ? Overview For Developer

Looks like Microsoft Great Plains becomes more and more popular,... Read More

Twelve Things You Should Know to Save on Computer Software

Do you want to get quality software at a reasonable... Read More

C++ Tutorial 2, Input and Variables

This is the tutorial where we really get into programming.... Read More

Who?s Watching What You Type?

If someone entered your home, uninvited and installed numerous cameras... Read More

Tripwire for Linux File Integrity

What is Tripwire?Tripwire is a form intrusion detection system (IDS)... Read More

Microsoft Navision Database Selection: C/SIDE or MS SQL Server - Overview For IT Specialist

There are certain pluses and minuses in both cases and... Read More

Instant Messaging is a Sweet Way to Communicate

MSN messenger is a pretty cool invention. I mean I'm... Read More

Microsoft Great Plains Integration Manager ? Working With Text File

Microsoft Business Solutions main middle market ERP application - Microsoft... Read More

An Easy Way to Develop JAVA Enterprise Applications

Research bears that less than 70 percent of development projects... Read More

Microsoft Great Plains e-Commerce ? additional considerations for programmer

Microsoft Great Plains, designed back in 1990th as database transferable... Read More

Dig Out That Worm

Internet worms. Is your PC infected?If your computer has become... Read More

Hear It in Digits

Music downloads are off the charts! We're listening to digital... Read More

Dont Choose Adobe When Working With PDF

While Adobe is the most known maker of PDF tools,... Read More

Spyware, Adware, etc. -- Terms and Common Sense

When reading an article where some term is used often,... Read More

Upgrading Great Plains Dexterity Customization ? switching to new technologies: SQL, Crystal, eConne

1. Replace Dexterity cursor with SQL Stored Procedure Dexterity... Read More

Most Common Ways to Accumulate Spyware (where It is Downloaded to Your PC)

It is possible that if one avoided all sources of... Read More

Microsoft Great Plains international implementation ? USA / Mexico ? overview for consultant

Microsoft Business Solutions Great Plains was purchased from Great Plains... Read More

Keep Your Software Simple! A Review of EditPlus

I like my software simple. If it's too complex or... Read More

Microsoft CRM Integration & Customization: SharePoint Document Gateway

MS CRM is very close to document workflow automation, including... Read More

Software Review: Xsitepro Total Site Management Software

It's not very often I get excited about a software... Read More

CROOK: A Methodology for the Refinement of Forward-Error Correction

Table of Contents1) Introduction 2) Related Work 3) Framework 4)... Read More

XML Parser and Their Types

XML parser is a software module to read documents and... Read More

The Bluebird Project

The objective for Zandi Digital is to make available clever... Read More

An Easy Way to Deal with Email Viruses and Worms

If you feel intimidated when someone tries to teach you... Read More