Week 4 Task 3

by Ken Wai Ooi

HTML

<script>
var n = prompt("Enter factorial number for n");
factorial = function(n)
{
 if(n < 0)
 {
 alert("Number have to be positive");
 
 return -1;
 }
 var rval = 1;
 for (var i = 2; i <= n; i++)
 {
 rval = rval * i;
 }
 return rval;

}
document.write(factorial(n));
</script>