JSFiddle - React, Tailwind, and code Playground

HTML

<input type="button" value="Click" id="thebutton"/>

JavaScript

var ar = [0, 1, 2, 3, 4, 5];
document.getElementById('thebutton').onclick = function() {
    var shuffle = [];
    var copyarr = ar.slice(0);
    var arlength = copyarr.length;
    for (i = 0; i < arlength; i++) {
        shuffle.push(copyarr.splice(Math.floor(Math.random() * copyarr.length), 1));
    }
    alert(shuffle.join(","));
};