Frameworks are collections of pre-written code that provide a structure for developers to build applications. Frameworks help developers save time by providing ready-made components and tools that can be used to quickly develop an application. In the JavaScript domain, popular frameworks include React, Angular, Vue, and Node.js. These frameworks provide developers with a set of features such as component-based development, routing, state management, and more. By using these frameworks, developers can create powerful web applications faster and easier than ever before.