A simple form that does nothing

Using Firefox browser on (at least) Windows, complete this German input by appending closing quote using Alt+0147!
Simple text entry:

Or complete that text by prepending the typographic opening quote using the same Alt+0147!
Simple text entry:

Misbehaviour: As soon as pressing the "4" key, the BACK function is activated, and text entered so far is lost. Same as you unintentionally pressed Alt+←. There is even no need to set the focus to text input.