Difference between Ajax and jQuery

Key difference: AJAX stands for Asynchronous JavaScript and XML. It is a group of web development programs used to design websites. The programs create interactive web applications using a combination of XHTML for basic programming, CSS for styling, DOM for interaction, data exchange using XML and XSLT, XMLHttpRequest and JavaScript. jQuery, on the other hand, is a multi-browser JavaScript library. jQuery is a free, open source software. It is licensed under the MIT License. It was designed to simplify the client-side scripting of HTML and is currently used by numerous websites.

AJAX stands for Asynchronous JavaScript and XML. It is a group of web development programs used to design websites. The programs create interactive web applications using a combination of XHTML for basic programming, CSS for styling, DOM for interaction, data exchange using XML and XSLT, XMLHttpRequest and JavaScript. AJAX enables web pages to send data to and receive data from a server without changing or hindering the web page itself. AJAX eliminates the need for the customers to wait, making interaction between the customer and the server asynchronous.

Google is the biggest known supporter of AJAX and has invested millions of dollars to advance it. Major Google products, such as Orkut, Gmail, Google Suggest, and Google Maps are AJAX applications. Amazon has also launched it’s own search engine, A9, on AJAX.

Ajax is not a single technology. It is a group of technologies. Jesse James Garrett, the one who coined the term, AJAX, lists the various technologies incorporated in AJAX:

HTML (or XHTML) and CSS for presentation
The Document Object Model (DOM) for dynamic display of and interaction with data
XML for the interchange of data, and XSLT for its manipulation
The XMLHttpRequest object for asynchronous communication
JavaScript to bring these technologies together

jQuery, on the other hand, is a multi-browser JavaScript library. jQuery is a free, open source software. It is licensed under the MIT License. It was designed to simplify the client-side scripting of HTML and is currently used by numerous websites. In fact, according to Wikipedia, it is used by over 55% of the 10,000 most visited websites. It is the most popular JavaScript library in use today. jQuery was released in January 2006 at BarCamp NYC by John Resig. However, it is currently developed by a team of developers led by Dave Methvin.

jQuery's syntax is designed to make it easier to navigate a document, select DOM elements, create animations, handle events, and develop Ajax applications. In addition to the JavaScript library, jQuery also provides capabilities for developers to create plug-ins. The advantage of this is that it enables developers to create abstractions for low-level interaction and animation, advanced effects and high-level, theme-able widgets. Furthermore, the approach to the jQuery library allows the creation of powerful dynamic web pages and web applications.

The main difference between JavaScript and jQuery is that while JavaScript is a scripting language, jQuery is a JavaScript library, which is extensible by a plugin mechanism. jQuery is a framework which is built in JavaScript in order to help programmers who work with common web tasks. jQuery exposes a number of utility functions that make programming in JavaScript easier. jQuery aims to make it easier for the programmers rather than have them work in raw JavaScript. It achieves this by extending the functionality of JavaScript.

jQuery also makes HTML document traversal and manipulation, event handling, animation, and Ajax much simpler with an easy-to-use API that works across a multitude of browsers.

The main difference between the two is that AJAX is a method to dynamically update parts of the UI without having to reload the page. It is a way to talk to the server in the background, while jQuery is a library/framework built with Javascript. jQuery is a JavaScript framework that makes life easier for people who want to program for the browser.

Some difference between Ajax and jQuery:

AJAX is a JavaScript Tool while jQuery is a JavaScript Library.
AJAX cannot be used with HTML, as HTML does not allow the page to reload part of the page once the page has already loaded. jQuery however does not have any such restrictions. It can effectively interact with HTML.
AJAX is a combination of several technologies, such as CSS, HTML, DOM, etc. Whereas, jQuery is a straightforward JavaScript library.
In addition to being a combination of technologies, Ajax provides new functionalities by combining the said technologies. jQuery cannot provide a new functionality by combining with other technologies.
Ajax should be accessed in a proper procedure to retrieve data from the server. jQuery can be accessed through front-end.
jQuery handles front end tasks while AJAX handles backend (server calls).
jQuery does not require understanding of the complete procedure to setup a page.
Heavy usage of Ajax may lead to overloading of the server due to the number of connections created. jQuery does not face such a problem.
AJAX and jQuery are often used together.
In order to use AJAX, one would need a client side scripting language that allows one to detect the actions of the user and modify elements on the page accordingly. jQuery does that.