This menu also has some other important features such as a menu scanning, scan text fields, scan buttons, move thumb , etc. The above scan-line configuration is ideal for sighted users that have limited motor movement. Auditory prompts can be added for those with visual impairments. In most applications this is the scroll bar screen. You can, however, move up and down pages with the PgUp and PgDn keys on the Macintosh extended keyboard, but these do not have an equivalent keystroke representations.
Frames are problematic.
If there are multiple frames on the screen but only one of them is scrollable, you must select that frame with a mouse button click before you can issue scroll down commands. Some unscrollable frames may need to be resized manually to view all the web page elements.