on click change color of text
<!DOCTYPE html>
<html>
<head>
<title>Change Color</title>
</head>
<body>
<button id="changeGreen">Change Font Color Green</button>
<button id="changeRed">Change Font Color Red</button>
<p>
<span id="output">Learn the test-driven development approach when building apps</span>
</p>
<script>
document.getElementById("changeGreen").onclick = function(){
document.getElementById("changeGreen").style.color = 'green';
}
document.getElementById("changeRed").onclick = function(){
document.getElementById("output").style.color = 'red';
}
</script>
</body>
</html>