jQuery is a JavaScript library that is frequently used in web development. It was developed to simplify working with JavaScript and to facilitate the development of interactive, appealing web applications.

jQuery offers a variety of functions and tools that enable developers to write JavaScript code quickly and easily. The library contains functions for manipulating HTML elements, event processing, animation, DOM manipulation and HTTP interaction.

By using jQuery, developers can often write code that is shorter and more efficient than traditional JavaScript code. In addition, jQuery enables the creation of interactive user interfaces that respond to user input and dynamically update data on the page.

jQuery is an open source library and can be downloaded from the official website. There are also a variety of plugins and extensions that have been developed by the community to extend the functionality of jQuery.

Overall, jQuery is an important library in web development that can help to simplify the development of appealing, interactive web applications.