JSFiddle - React, Tailwind, and code Playground

by btipling

HTML

<button>First button</button>
<button>Second button</button>
<button>Second button</button>

JavaScript

var button, wmap = new WeakSet();

for (button of document.querySelectorAll("button")) {
    button.addEventListener("click", function (event) {
        if (wmap.has(event.target)) {
            alert("You have clicked this button before!");
        } else {
            alert("First time clicking this button");
        }
        wmap.add(event.target);
    });
}