<!DOCTYPE html>
<html>
<body>
<span>Click to Change random Color</span>
<br />
<br />
<div id="results"></div>
<script type='text/javascript'>
var body;
var button;
body = document.querySelector('body');
button = document.querySelector('span');
function changeColor() {
var color = '#'+Math.floor(Math.random()*16777215).toString(16);
body.style.background = color;
document.getElementById('results').innerHTML += color + '<br />';
}
button.onclick = changeColor;
</script>
</body>
</html>