programmatically press keyboard key on button click event

Question

I have one textbox & button. On button click event I have too show some keyboard value (example I have to show number 2 into a textbox)

 

How can I do a javascript code which will automatically press a key & show a text into a textbox.

 

I tried with below code. Suggest me something.

Thanks in advance. 

<input type="text" id="myInputTextBoxId" value="">
<button id="myButton" type="button">Generate Text</button>

<script>
document.getElementById("myButton").addEventListener("click", function() {
        var press = jQuery.Event("keypress");
        press.which = 50;
        $('#myInputTextBoxId').trigger(press);
        $('#myInputTextBoxId').focus();
});
</script>