What term refers to the Web 2.0 programming methodology that allows Web applications to interact similarly to desktop applications?

The correct answer is Ajax. Ajax, which stands for Asynchronous JavaScript and XML, is a programming methodology that enables web applications to communicate with a server in the background without interfering with the display and behavior of the existing page. This approach allows for smoother user experiences by facilitating operations like data retrieval, submission, and updates without requiring a full page reload, which is similar to how desktop applications operate.

By utilizing JavaScript and leveraging XMLHttpRequest, Ajax can asynchronously send and receive data from the server, allowing for dynamic content updates and improved responsiveness. This ability to fetch data in the background significantly enhances the interactivity and performance of web applications, a hallmark of Web 2.0 technologies.

While other options include technologies relevant to web development, they do not embody the specific interactive and dynamic characteristics of desktop application-like behavior that Ajax provides. XML and JSON are data interchange formats that can be used in conjunction with Ajax but do not define the interactive methodology itself. JavaScript is a programming language used within Ajax, but it does not encapsulate the full asynchronous communication aspect that Ajax represents.