Auto tab to next field

[Jeff Honken]

I trying to program an automatic tab to the next field after the user
inputs three characters.  Here's the code I'm using:

on keyDown theKey
  if the number of chars in me >= 3 then
    focus on fld ProvOfficePhone2
    exit keyDown
  else
    pass keyDown
  end if
end keyDown

The above code works but when I hit the fourth character it tabs to the
next field but it loses the character that was typed. i.e. if you type
1234 the 123 goes into my first box and the cursor goes to the next
field but it doesn't input 4 into that field.  Any suggestions?  Jeff