JSFiddle - React, Tailwind, and code Playground

HTML

<button>Greet</button><br><br>

JavaScript

// use this function when you create variables.
// instead of   var someVariable = "someValue";
// use          var someVariable = v("someValue");
// this will output the value, and still assign the variables as you'd expect. 

function v(value) {
    var outputText = (typeof value === "object" && value.constructor === Object && window.JSON) ? JSON.stringify(value) : value;
    document.body.appendChild(document.createTextNode(outputText));
    document.body.appendChild(document.createElement("br"));
    return value;
}

// create and output a "greeting" variable
var greeting = v("Hello There!");

// create and output an array of primary colours
var primaries = v(["red", "green", "blue"]); 

// say the "greeting" variable when you click the button
document.getElementsByTagName("button")[0].onclick = function() {
    alert(greeting);
};