How to select a button and display the value of it to the screen

I want to be able to select from a list of buttons and this display to the screen the value of that button. I have a function but im not sure what parameters to have within the HTML or function.

    <input type="button" class="button" id="button2" value="2" onclick="click(this)">
    <input type="button" class="button" id="button3" value="3" onclick="click(this)">
    <input type="button" class="button" id="button4" value="4" onclick="click(this)">

function click(button){
    var buttonclicked = document.getElementById(button.id).value;
    firstbox.innerHTML = "Your Chosen button is: " + buttonclicked;
    button.disabled = true;
}