write javascript code for arithmetic expression evaluation and print the result using message box.(accept the values from user)

<script>
function evaluate(){
var a=parseInt(document.getElementById("a").value);
var b=parseInt(document.getElementById("b").value);
var c=parseInt(document.getElementById("c").value);
var d=parseInt(document.getElementById("d").value);
var e=parseInt(document.getElementById("e").value);
var f=parseInt(document.getElementById("f").value);
var g=parseInt(document.getElementById("g").value);
var h=parseInt(document.getElementById("h").value);
var i=parseInt(document.getElementById("i").value);
var result;
result=a+b+c+d+e+f+g+h+i;
alert(result);
}
</script>