JSFiddle - React, Tailwind, and code Playground

HTML

<button id="my_btn">Click Me</button>
<input id="fielda" placeholder="Type Something Here" />
<output id="result">Output Will Appear Here</output>

JavaScript

document.addEventListener("DOMContentLoaded", function(){
    document.getElementById("my_btn").addEventListener("click", function(){
        var fieldAValue = document.getElementById("fielda").value;
        alert(fieldAValue);
        document.getElementById("result").textContent = "Result: "+fieldAValue;
    }, false);
}, false);