if what you are trying to do is to remove the "highlight" of fields which the application is applying by default to all the filling fields there is one line of code which will do exactly as you wish, but it will also apply the setting to the whole form.
//False: remove highlight of all fields within the form
//True: apply highlight of all fields within the form
app.runtimeHighlight = false;
The user can still remove the highlight by changing the setting using the application.