AJAX and PHP Building Responsive Web Applications

Enhance the user experience of your PHP website using AJAX with this practical tutorial featuring detailed case studies

Cristian Darie is a software engineer with experience in a wide range of modern technologies, and the author of numerous technical books, including the popular "Beginning E-Commerce" series. Having worked with computers since he was old enough to press the keyboard, he initially tasted programming success with a first prize in his first programming contest at the age of 12. From there, Cristian moved on to many other similar achievements, and now he is studying distributed application architectures for his PhD degree. He always loves hearing feedback about his books, so don't hesitate dropping a "hello" message when you have a spare moment.

Filip Cherecheş-Toşa is a web developer with a firm belief in the future of web-based software. He started his career at the age of 9, when he first got a Commodore 64 with tape-drive.

Back home in Romania, Filip runs a web development company named eXigo www.exigo.ro, which is actively involved in web-based application development and web design. He is currently a student at the University of Oradea, studying Computer Science, and also an active member of the Romanian PHP Community www.phpromania.net.

Mihai Bucica started programming and competing in programming contests (winning many of them), all at age twelve. With a bachelor's degree in computer science from the Automatic Control and Computers Faculty of the Politehnica University of Bucharest, Romania, Bucica works on building communication software with various electronic markets.

Even after working with a multitude of languages and technologies, Bucica's programming language of choice remains C++, and he loves the LGPL word. Mihai also co-authored Beginning PHP 5 and MySQL E-Commerce and he can be contacted through his personal website, www.valentinbucica.ro.

Emilian Balanescu is a programmer experienced in many technologies, including PHP, Java,
.NET, PostgreSQL, MS SQL Server, MySQL, and others. He currently works as a Wireless
Network Administrator at accessNET International S.A. Romania, a company that provides fixed wireless access services operating a point-to-multipoint digital radio communication network with national coverage. His latest project in this position was developing an AJAX-enabled real-time Network Management System (using SNMP, Perl, PHP, and PostgreSQL) used for remote debugging, monitoring system performance, and isolating and troubleshooting system problems. You can reach Emilian at http://www.emilianbalanescu.ro.

Paula Badascu is in the third year of studies at Politehnica University of Bucharest, one of the most famous technical universities in Romania, studying Electronics, Telecommunications, and Information Technology. Paula is currently working as an analyst/programmer for NCH Advisors Romania, building web applications using UML, OOP, PHP, SQL, JavaScript, and CSS. She contributed decisively to the analysis and development of a framework used for tracking and monitoring the Romanian capital market.

AJAX is a complex phenomenon that means different things to different people. Computer users appreciate that their favorite websites are now friendlier and feel more responsive. Web developers learn new skills that empower them to create sleek web applications with little effort. Indeed, everything sounds good about AJAX!

At its roots, AJAX is a mix of technologies that lets you get rid of the evil page reload, which represents the dead time when navigating from one page to another. Eliminating page reloads is just one step away from enabling more complex features into websites, such as real-time data validation, drag and drop, and other tasks that weren't traditionally associated with web applications. Although the AJAX ingredients are mature (the XMLHttpRequest object, which is the heart of AJAX, was created by Microsoft in 1999), their new role in the new wave of web trends is very young, and we'll witness a number of changes before these technologies will be properly used to the best benefit of the end users. At the time of writing this book, the "AJAX" name is about just one year old.

AJAX isn't, of course, the answer to all the Web's problems, as the current hype around it may suggest. As with any other technology, AJAX can be overused, or used the wrong way. AJAX also comes with problems of its own: you need to fight with browser inconsistencies,
AJAX-specific pages don't work on browsers without JavaScript, they can't be easily bookmarked by users, and search engines don't always know how to parse them. Also, not everyone likes AJAX. While some are developing enterprise architectures using JavaScript, others prefer not to use it at all. When the hype is over, most will probably agree that the middle way is the wisest way to go for most scenarios.

In AJAX and PHP: Building Responsive Web Applications, we took a pragmatic and safe approach by teaching relevant patterns and best practices that we think any web developer will need sooner or later. We teach you how to avoid the common pitfalls, how to write efficient AJAX code, and how to achieve functionality that is easy to integrate into current and future web applications, without requiring you to rebuild the whole solution around AJAX. You'll be able to use the knowledge you learn from this book right away, into your PHP web applications.

We hope you'll find this book useful and relevant to your projects. For the latest details and updates regarding this book, please visit its mini-site at http://ajaxphp.packtpub.com.

The book's mini-site also contains additional free chapters and resources, which we recommend you check out when you have the time.

Chapter 1: AJAX and the Future of Web Applications is an initial incursion into the world of AJAX and the vast possibilities it opens up for web developers and companies, to offer a better experience to their users. In this chapter you'll also build your first AJAX-enabled web page, which will give you a first look of the component technologies.

Chapter 2: Client-Side Techniques with Smarter JavaScript will guide you through the technologies you'll use to build AJAX web clients, using JavaScript, the DOM, the XMLHttpRequest object, and XML. While not being a complete tutorial for these technologies, you'll be put on the right track for using them together to build a solid foundation for your future applications.

Chapter 3: Server-Side Techniques with PHP and MySQL completes the theoretical foundation by presenting how to create smart servers to interact with your AJAX client. You'll learn various techniques for implementing common tasks, including handling basic JavaScript security and
error-handling problems.

Chapter 4: AJAX Form Validation guides you through creating a modern, responsive, and secure form validation system that implements both real-time AJAX validation and server-side validation on form submission.

Chapter 5: AJAX Chat presents a simple online chat that works exclusively using AJAX code, without using Java applets, Flash code, or other specialized libraries as most chat applications do these days.

Chapter 6: AJAX Suggest and Autocomplete builds a Google Suggest-like feature, that helps you quickly find PHP functions, and forwards you to the official help page for the chosen function.

Chapter 7: AJAX Real-Time Charting with SVG teaches you how to implement a real-time charting solution with AJAX and SVG. SVG (Scalable Vector Graphics) is a text-based graphics language that can be used to draw shapes and text.

Chapter 8: AJAX Grid teaches you how to build powerful AJAX-enabled data grids. You'll learn how to parse XML documents using XSLT to generate the output of your grid.

Chapter 9: AJAX RSS Reader uses the SimpleXML PHP library, XML, and XSLT to build a simple RSS aggregator.

Chapter 10: AJAX Drag and Drop is a demonstration of using the script.aculo.us framework to build a simple list of elements with drag-and-drop functionality.