JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="id">
        <li>iteam 1</li>
        <li>iteam 2</li>
        <li>iteam 3</li>
        <li>iteam 4</li>
     </ul>
  <body>

CSS

.active {
    color: blue;
}

JavaScript

(function() {
    var id = document.getElementById("id");
    var liele = id.getElementsByTagName("li");
    for (var i = 0; i < liele.length; i++) {
        liele[i].addEventListener("click", function () {
            this.className = "active";
        })

    }
})();