Installing & Downloading Jquery

In this section we will download and install jQuery for developing our demo application. jQuery comes as single js file. So, its very easy to download and install jQuery in any web application. You can even add it to your existing application and use jQuery functions. Due to this simplicity programmers are using jQuery for adding Ajax capabilities into their web applications.

The latest version of jQuery at the time of writing of this tutorials is 1.2.6. But you can download the latest version of jQuery from its official site http://jquery.com/
Visit http://jquery.com/ and download jquery-1.2.6.min.js and add into js directory of your application. You can rename it to jquery-1.2.6.js.

You are now all set and ready to add the jQuery support into your web application.

In the next section we will show you how you can develop your first Ajax jQuery application that shows the current server time.

What is jQuery?

jQuery is great library for developing ajax based application. jQuery is great library for the JavaScript programmers, which simplifies the development of web 2.0 applications. You can use jQuery to develop cool web 2.0 applications. jQuery helps the programmers to keep code simple and concise. The jQuery library is designed to keep the things very simple and reusable.

jQuery is great library for developing ajax based application. jQuery is great library for the JavaScript programmers, which simplifies the development of web 2.0 applications. You can use jQuery to develop cool web 2.0 applications. jQuery helps the programmers to keep code simple and concise. The jQuery library is designed to keep the things very simple and reusable.

jQuery library simplifies the process of traversal of HTML DOM tree. You can use jQuery to handle events, perform animation, and add the ajax support into your web applications with ease.

Why jQuery?

You can use simple JavaScript to perform all the functions that jQuery provides. Then why jQuery? The jQuery library is providing many easy to use functions and methods to make rich applications. These functions are very easy to learn and even a designer can learn it fast. Due to these features jQuery is very popular and in high demand among the developers. You can use jQuery in all the web based applications irrespective of the technology.


jQuery is java script and can be used with JSP, Servlets, ASP, PHP, CGI and almost all the web programming languages.

The jQuery code is very simple and easy to learn.

Here are the features of jQuery
DOM element selections functions
DOM traversal and modification
Events
CSS manipulation
Effects and animations
Ajax
Extensibility
Utilities - such as browser version and the each function.
JavaScript Plugins

How much time is required to learn jQuery?

You can learn jQuery in a day and master it within 2-3 days. There are so many features available with jQuery and you may spend months to explore these features.

We have spent huge time in exploring the jQuery and developing almost all the examples that can be developed with jQuery. So, explore our huge collection of jQuery tutorials and examples. Please continue reading the tutorials.

What is Ajax?

If you're like most PHP developers, you probably learned your craft the old-fashioned way. You learned how to define and build simple PHP pages, connect them to simple MySQL tables, and off you went. As you progressed through various skill levels, you learned how to create ever-more complex PHP functionality, and you learned how to join tables in MySQL and perform other advanced tasks.
Along the way, you probably picked up a number of client-side skills to bring your Web applications to life. You may have learned a bit about XHTML or CSS, maybe some JavaScript programming. Depending on the kinds of projects you're used to, you may even have had the chance to work with Ajax to give your Web applications that Web 2.0, or "desktop," feel. If your first experience with Ajax was anything like mine, however, you probably did too much work — hand-rolling your functions and struggling through the process of creating an Ajax-driven page.

Frequently used acronyms

• CSS: Cascading Style Sheet
• HTML: Hypertext Markup Language
• XHTML: Extensible Hypertext Markup Language
• XML: Extensible Markup Language

For some, Ajax is still a mystery. It's something that the "cool kids" and "bad boys" of Web development/interactivity do, and they've never had the time, patience, or skill to take it on. It's a shame, too, because a lot of clients really like adding Ajax-style functionality — it makes Web applications easier to work with. If you're one of these PHP developers, never fear: By the time you're done reading this article, you'll know enough to become a real Ajax pro.
This article shows how to use jQuery to easily add Ajax functionality to any PHP Web application. You'll build a simple Web application with PHP and MySQL — a phone book containing names and phone numbers. The application has all the standard things you'd expect — a way to search for names or phone numbers, a MySQL table, etc. Next, you'll add jQuery to the application, giving you the ability to search for names and phone numbers in real time, as you type. When you're done, you should have a pretty good grounding in not only some jQuery basics but also in the fundamentals of Ajax.

The best way to describe Ajax is to compare it to what you already know. Most Web pages and applications work in synchronous mode. You click a link or a form's Submit button, and the request is sent to the server, which then processes that request and sends back a response. The best way to sum up this model is "click, wait, view." It's a never-ending rinse-and-repeat cycle that you know all too well. In other words, if your page needed to show constantly updated information, you either had to put in some kind of auto-refresh hack or make the user refresh or click a link to make things happen.
Ajax changes all that. The first A in Ajax stands for asynchronous. Ajax allows you to create a page in any programming language, then refresh different parts of that page with information from a database or some other back-end server process. For example, say you have an e-commerce site that shows products for sale. On each product page, there are the usual items: headlines, sales copy, thumbnail photos, the number of items in stock.
Say you wanted to keep the site visitor updated on how many items were in stock. You could add an Ajax function that would run a separate PHP page containing a MySQL query, then repopulate the information on the original page without any input from the user or without regard to the synchronous nature of the click-wait-view pattern of events.
The j in Ajax stands for JavaScript, and that's what powers all the behavior you get. That's a blessing and a curse, really — a blessing because it's all client-side code, so it's portable and doesn't affect the server; a curse for a lot of PHP developers because it's a different environment than they're used to. That's where tools and frameworks like jQuery come in: They vastly simplify how you interact with Ajax, speeding our time to code completion.
What about the final two pieces: the + and the x? They stand for and XML, although the XML part is sometimes not really true. Plenty of Ajax applications work well without any XML code at all: They merely pass HTML or even plain text back and forth. It's probably more accurate to have the x stand for XMLHttpRequest, as you're using that object to retrieve data in the background, thereby not interfering with the display or behavior of the existing page.