JSFiddle - React, Tailwind, and code Playground

HTML

<button type="button" id="1">Click</button>
<button type="button" id="2">Click</button>
<button type="button" id="3">Click</button>
<button type="button" id="4">Click</button>
<button type="button" id="5">Click</button>

JavaScript

var buttons = document.getElementsByTagName("button");
var buttonsCount = buttons.length;
for (var i = 0; i < buttonsCount; i++) {
    buttons[i].onclick = function(e) {
        alert(this.id);
    };
}