change color by click event javascript

1<script>
2
3    document.getElementById('change').onclick = changeColor;   
4
5    function changeColor() {
6        document.body.style.color = "purple";
7        return false;
8    }   
9
10</script>

1var button = document.querySelector("button");
2
3button.addEventListener("click", function() {
4    const curColour = document.body.style.backgroundColor;
5
6    document.body.style.backgroundColor = curColour === 'red' ? 'blue' : 'red';
7});
8

1const btn = document.querySelector('button');
2
3function random(number) {
4  return Math.floor(Math.random() * (number+1));
5}
6
7btn.onclick = function() {
8  const rndCol = 'rgb(' + random(255) + ',' + random(255) + ',' + random(255) + ')';
9  document.body.style.backgroundColor = rndCol;
10}