Express.js and jQuery are two different technologies used for different purposes in web development. Express.js is a server-side web application framework built on top of Node.js. It is used to create web applications that handle HTTP requests and responses, and provides features like routing, middleware, and template engines. Express.js is mainly used for building server-side applications and APIs. jQuery, on the other hand, is a JavaScript library that simplifies HTML document traversing, event handling, and AJAX interactions for client-side scripting. It provides an easy-to-use API for manipulating HTML documents and handling events, and simplifies the process of making AJAX requests to the server. The main difference between Express.js and jQuery is that Express.js is a server-side framework used for building web applications on the server side, while jQuery is a client-side library used for manipulating HTML documents and making AJAX requests from the client-side. In summary...