<html>
<body>
<p id="demo">Click the button to display the cosine value of PI and 2*PI.</p>
<button onclick="myFunction()">Try it</button>
<script>
function myFunction()
{
var a=Math.cos(Math.PI);
var b=Math.cos(2*Math.PI);
document.getElementById("demo").innerHTML=a + "<br>" + b;
}
</script>
</body>
</html>