Action-response models (a sub-category of SeparatedConcerns) separately define presentation pages (often called views), controller-specific code and other code. A URL is mapped to specific controller code (Actions in Struts, for example). Upon a request, the invoked controller code should in turn invoke model code and then determine, based on the outcome of such an invocation, which view to render in response to the request. Instead of immediately returning a response, such controller code can also instruct the browser to fetch a view from a different URL.
In the Java world, the basic models of model 2 architectures roughly operate in this way. (See http://www.javaworld.com/javaworld/jw-12-1999/jw-12-ssj-jspmvc.html) A model 2 architecture includes Java programming language code (some of which is used to handle controller concerns explicitly), and separate presentation code (typically templates, such as JSP) for rendering HTML pages.