jQuery has a very powerful interface with a host of important features.
DOM Manipulation: You can select DOM elements and modify their content using Sizzle, an open-source selector engine that is browser independent. You can add and remove elements, modify CSS class, HTML content etc.
DOM Selection: jQuery lets the developers retrieve DOM elements on the basis of existing CSS selectors and also provides some custom selectors that can retrieve elements based on a variety of criteria.
AJAX Support: jQuery helps developers to build an interactive platform using AJAX functions. The AJAX technology also allows the loading of data even when the whole page is not being reloaded.
Event Handling: jQuery captures a wide array of events that are parallel to a number of DOM events like dblclick, click, mouseenter, blur, keydown, keyup, mouseleave. These events equip jQuery to deal with any cross-platform issue.
Special Effects: jQuery has a number of built-in effects like animation, sliding effect, hiding elements, fade-out or fade-in of visibility etc.
Cross-browser Support: jQuery works across browsers like Chrome 9.0+, IE 6.0+, Opera 9.0+, Safari 3.0+, FF 2.0+ etc.
Lightweight: jQuery is a very small and efficient library that is just about 19 kb in size.
Latest Technology: jQuery supports basic XPath Syntax and CSS3 Selectors.
There are two ways in which you can use jQuery- Local Installation and CDN based version.
CDN Based Version: In this process, you do not need to install jQuery locally on your machine. You can directly include it in your HTML code from the Content Delivery Network (CDN).
Read here jQuery Interview Questions and Answer