JSFiddle - React, Tailwind, and code Playground

HTML

<form>
   <input type="text" id="number" value="0"/>
   <input type="button" onclick="incrementValue()" value="Increment Value" />
</form>

JavaScript

function incrementValue()
{
    var value = parseInt(document.getElementById('number').value, 10);
    value = isNaN(value) ? 0 : value;
    value++;
    document.getElementById('number').value = value;
}