Javascript/FOR loop

Hi
Does anyone here know how to use the FOR loop in javascript
if yes then can they show me how to write a 20 times table.

<script type="text/javascript"> var i = 0 var num = 20 for (i=1; i <= 10; i++) { document.write(i + " times 20 is " + num) document.write("<br />") num = num + 20 } </script>
That’ll print them, change the code to suit.