jQuery is a great library for developing ajax based application. It is a 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.

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.

JQuery 1.4 Released

In celebration of jQuery’s 4th birthday, the jQuery team released the latest major release of the jQuery JavaScript library! A lot of coding, testing, and documenting has gone into this release, and I am really quite proud of it.

I want to personally thank John Resig for birthing this project and inspiring us to be better Web / Ajax Developers with such an amazing tool.

JQuery 1.4 Features

Performance Improvements For Methods

Many of the most popular and commonly used jQuery methods have seen a significant rewrite in jQuery 1.4. When analyzing the code base some significant performance gains were made by comparing jQuery against itself: Seeing how many internal function calls were being made and to work to reduce the complexity of the code base.
jQuery 1.4 Performance Improvements

In jQuery 1.4 the complexity of the most popular methods has significantly reduced. I also like the quick element construction functionality now in place, such that you when create a single element with the jQuery function, you can now pass in an object to add attributes and events at the same time :

jQuery("<div/>", {

    id: "foo",
    css: {
        height: "50px",
        width: "50px",
        color: "blue",
        backgroundColor: "#ccc"
    },
    click: function() {
       $(this).css("backgroundColor", "red"); 
    }
}).appendTo("body");

The code snnipet above resembles development with ExtJs. JQuery 1.4 also attempted to minimize any large upgrade hassles – maintaining the signatures of all public functions this means that they made sure this new mega release is backwards compatible. I like to explore new technologies so I am upgrading right away.