A web client consists of two parts:
Dynamic web pages containing various types of markup language (HTML, XML, and so on), which are generated by web components running in the web tier
A web browser, which renders the pages received from the server
A web client is sometimes called a thin client. Thin clients usually do not query databases, execute complex business rules, or connect to legacy applications. When you use a thin client, such heavyweight operations are off-loaded to enterprise beans executing on the Java EE server, where they can leverage the security, speed, services, and reliability of Java EE server-side technologies.