In computing, a user interface is the space where interaction between humans and machines occurs. A rich user interaction is an interface model of a rich client. It is an interaction model that can support several input methods and that responds intuitively and in a timely fashion. As a rule of thumb, to be a rich user interaction, the model must perform in practice at least as well as current desktop applications, such as word processors and spreadsheets.
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Rich user interaction Wikipedia(Text) CC BY-SA