1. A method for efficiently encoding navigational state in a Portal, wherein said Portal is running in a server system, wherein said server system includes a communication component which allows communication between said Portal and a client's browser via a communication channel, wherein said Portal determines a layout of a Portal page, invokes rendering of a plurality of page elements belonging to said Portal page, and transmits said Portal page to the client's browser for displaying, wherein at least one of said page elements belonging to said Portal page provides a URL for initiating rendering of a new page or new page element by said Portal, wherein each user interaction by clicking said URL at said page element generates a new navigational state at said Portal, wherein a latest navigational state describes a current view of said Portal resulting from all previous navigational interactions of said client, wherein at least said latest navigational state is saved by said Portal, wherein in response to a client request for a new Portal page said method is characterized by the steps of: creating a base navigational state which describes a part of the latest navigational state that is identical across a plurality of URLs in said new Portal page, creating for each of said URLs in said new Portal page a URL specific delta navigational state which describes a state transition to obtain a new base navigational state by merging said URL specific delta navigational state with said base navigational state when a corresponding one of said URLs is invoked, wherein said URL specific delta navigational state is not contained in said base navigational state, encoding said base navigational state once into a header portion of markup of said new Portal page once, encoding said URL specific delta navigational state into its corresponding one of said URLs as part of a body portion of said markup of said new Portal page, and generating and transmitting a response to said client's browser including said markup of said new Portal page for displaying by said client's browser.