JSFiddle - React, Tailwind, and code Playground

HTML

<button id="button">one</button>
<button id="button2">two</button>

JavaScript

button = document.getElementById("button");
button2 = document.getElementById("button2");

(function() {
    var x = 5;
    
    button.onclick = function() {
        alert(x);
    }
})();

(function() {
    var x = 10;
    
    button2.onclick = function() {
        alert(x);
    }
})();