The Script:
<script type="text/javascript"> function multiply(){ var tot=1,a=arguments,b=a.length; for(var i=0;i<b;i++){ if(isNaN(a[i]) || !a[i]){continue;} tot*=a[i]; } return tot; } </script>
The example:
<script type="text/javascript"> alert(multiply(1,2,3,4,5)); </script>
Try it
More Maths.