The present invention enables a focus to be moved easily among focus items in different frames when frames are displayed. To do so, the last focused item in an in-frame document once activated is stored (S11) and, when a frame movement event is caused by a focus movement operation (S12, Yes), the focus is moved to a focus item stored for a new frame (S13). If the stored focus item is not in the display area of the frame, the focus is moved preferably to a predetermined (for example, the first) focus item in the display area. Operation means for the focus movement operation may be used with frame switching means for switching the active frame among frames.