Answer No : 2 : 
<html>
<head>
<title>My Program</title>
</head>
<body>
val1:<input type="text" id="val1box">   
<br/>
<br/>
val2:<input type="text" id="val2box">
<br/>
<br/>
<button type="submit" onclick="myf1()">add</button>
<button type="submit" onclick="myf2()">multiple</button>
<br/>
<br/>
output:<input type="text" id="outputbox">
<script>

function myf1()
{
var a=document.getElementById("val1box").value;
var b=document.getElementById("val2box").value;
var c=parseInt(a)+parseInt(b);
document.getElementById("outputbox").value=c;
}

function myf2()
{
var a=document.getElementById("val1box").value;
var b=document.getElementById("val2box").value;
var c=parseInt(a)*parseInt(b);
document.getElementById("outputbox").value=c;
}
</script>
</body>
</html>
Output: