Edit

GetFieldName (windowRef, fieldNum)

Result Type:  text

Definition:  Get the symbolic name for a UI field from its index.

Allows you to get symbolic names of fields by iterating over the field numbers.

Example:  To get a list of all of the symbolic field names in a window, activate the following script and then open the window of interest; then look in the log file (and deactivate the script). 

on Before(w)
    Syslog(The window ID is " + GetWindowID(w))
    foreach f in (1, GetFieldCount(w))
        syslog(f + " " + GetFieldName(w, f))
    endfor
end

For the standard Transaction entry window, you'll get something like: 

The window ID is F_TRANS
1 L_LINE
2 M_TABS
3 L_LIST
4 L_ENTRY
5 T_WOFFACCTDESC
6 T_PRODDESC
7 E_NAME
8 E_USERREF
9 E_DATE
10 M_PERIOD
11 M_BANK
12 E_ORDERNUM
....

Another way, assuming you are only interested in edit fields: 

on EnterField(win, item)
    Navigator("", item)
end

This will display a tooltip for every field in every window† as the field is activated.

†Note that the Script Editor window itself does not receive script events.

Availability:  available within MWScript handlers.

See Also:

GetFieldCount: Get the number of controls in a window (standard or custom)

GetFieldCount GetFieldNumber