A keystroke mapping utility may be able to do this. Although a cntrl - arrow would probably be needed.
Google "windows keystroke macro"
A voice control program may work. Dragon is often suggested.
What Operating system do you have? Ctrl-up arrow and Ctrl-down arrow move you upd and down through a list or table view of records on a windows system.
Recent versions of the Mac system have interfered with these options, but you can restore them.
From the Filemaker Training Series, Pg 1-16:
Mac OS Lion shortcuts:
This key command [Control-up/controldown] is not functional in Mac OS X Lion wihout certain alterations. To re-enable this function, open System Preferences > Mission control. In the keyboard and mouse Shortcuts section, you will see tht the default setting has Mission control and Application windows using the up/down arrows. Change those settiings either to a different keystroke or to - [blank], depending on your preference.
I'm using Windows 07. I have what I think would be a typical problem. I have a layout based on a parent record with with a portal based on a child table. There can be many records in the portal. My users often need to navigat the portal. What's happening now is that they must tab through each field in a record to get to the next record. The other option that works, but is also not efficient, is to use the mouse on the scroll bar and then mouse to the record when found. What I would like is for them to simply use the up or down cursor keys. Control up or down would be acceptable, but that changes the Parent record - and of course the related portal. I have devised a find script that will keep the current parent record locked, but it does not help with the portal navigation issue (control up/down will change the record number in the status tool bar, but the field focus on the portal does not change).
Take a look at the OnObjectKeystroke script trigger. You can set this on each of the fields in the portal, for example, or on the entire layout in some cases by using OnLayoutKeystroke. THis can perform a script that checks the keystroke (get (TriggerKeystroke) ) and uses go to portal row to move up or down the portal when the up or down arrow is pressed.