Moment.js is a JavaScript library that simplifies working with dates and times in web applications. It provides a user-friendly API for tasks such as parsing, manipulating, formatting, and displaying dates and times. With Moment.js, developers can effortlessly handle various time-related operations, including calculations, comparisons, and conversions between different time zones. It also offers features for localization, allowing dates to be displayed in different languages and formats based on user preferences. Although Moment.js has been deprecated since September 2020, it remains a widely used library, providing a convenient solution for managing date and time functionality in JavaScript applications.