High- fidelity prototyping
-visualize requirement in detail
-Discover usability issue, especially with interactive behavior
-Develop a UI specification
-High-Fidelity prototypes reach from more detailed paper prototypes to fully interactive simulations
-From the level of detail of HTML prototypes on, users can see dialog windows,react on messages and enter from data
-show the real system behaviour in an interactive manner rather than just presenting static screens.