The GetWindowName$ function returns the name of the window specified by its handle.
Used to retrieve a window name which can then be used in a UseWindow statement.
<handle>, integer, window handle.
var$, string, name of the window. If no window with this <handle> is found, no error is reported and the return value is empty (an empty string is "").
'Retrieve the handle of the focused window
'a$ contains the window name of Edit notepad window (the focused one).