A viewport provides a window on the form for viewing a larger field. The end user uses the viewport's scroll bars to view undisplayed portions of the field in the viewport. A viewport can contain one field of any type.

Using a viewport lets you add a field to a form that would not otherwise fit in a specified area. Viewports are most often used for images or subforms because you can set the height and width of the work area (inner rectangle) of a viewport.