How can ı make onether button for post data?

If you are using Bootstrap the "input-group-addon" class was dropped in 4.x as far as I know and replaced with "input-group-prepend" or "input-group-append".

A simple way to add a button to fire your Javascript is to use something like 

<button type="button" class="btn btn-primary" onclick="vkn_kontrol();">VKN</button>

Without knowing how you expect the button to fit with the rest of your interface it is difficult to suggest other options.

 I am still learning Bootstrap so I am sure others will have a better answer.