jQuery is a popular, fast, and lightweight JavaScript library designed to simplify HTML document traversal and manipulation, event handling, animation, and Ajax interactions. Here are some key points about jQuery:

• Simplifies JavaScript: jQuery makes it easier to use JavaScript on your website by wrapping many common tasks into methods that can be called with a single line of code.
• Cross-Browser Compatibility: It ensures that your code works consistently across different browsers.
• Rich Features: jQuery includes features for HTML/DOM manipulation, CSS manipulation, event handling, effects and animations, and Ajax.
• Extensible: It allows developers to create plugins on top of the JavaScript library, enabling the creation of powerful dynamic web pages and web applications.
• Widely Used: As of August 2022, jQuery is used by 77% of the 10 million most popular websites.