JSFiddle - React, Tailwind, and code Playground

by karin

HTML

<p id="test"></p>

JavaScript

var a = [3, 2, 3, 3, 4, 3];

function checkArray(a) {
    for (var i = 1; i < a.length; i++) {
        if (a[i - 1] === a[i]) {
            alert(a[i]);
            document.getElementById("test").innerHTML = a[i];
        }
    }
}
checkArray(a);