Javascript Example
Screen shot
Javascript code to Add two Number
<html>
<head>
<script type=\"text/javascript\">

function add()
{
var num1=prompt(\"Enter I Number\");
var num2=prompt(\"Enter II Number\");
var num3;
num3=Number(num1)+Number(num2);
document.getElementById(\"result\").innerHTML=num3;
}

</script>
</head>
<body>

Click on Button to Add two number <br><br>
<input type=\"button\" onClick=\"add()\" value=\"Add Two Number\" />

<br /><br />

<div id=\"result\"></div>

</body>
</html>

You can download source code here