Terminal Browser trigger WEB HTML input onchange

we're trying to do something in our project. We're using C# for our web application and be able to use an external device for it. But we have some small problem,

we're trying to send the value from the external device to the Terminal Browser's HTML input field but it doesn't trigger onchange function.

We found some answers; We have to use a button to trigger the change, but we prefer to use the onchange in the input field instead. Is It possible and how? and why not?