Simple javascript question

I'm sure this is pretty basic stuff for the people on this board, but I'm just learning javascript so I'm struggling the like the said little lurker I am.

I have an assignment due tomorrow that requires me to write a page that requests the first and last numbers of a sequence from the user and then takes those two numbers and every number in between and displays a table with the numbers and their squares and cubes.

I really thought the script I had written would get it done but after the user enters the second number nothing happens and it just ignores the loop I wrote in. If anyone could tell me what is wrong with my script (posted below) or a different way to do it I would be grateful. I would like to avoid using functions for now as I am still a newb and am not particularly fond of them though I know I will be needing to use them alot at some point. Any help would be great anon!

<script language="Javascript" type="text/javascript">
        <!-- Hide script from old browsers
       
        document.write('<center><table width="50%" border="1">');
        document.write('<tr align="center"><td>' + "Numbers" + '<\/td><td>' + "Square" + '<\/td><td>' + "Cube" + '<\/td><\/tr>');
       
        ans = prompt("Enter the first number of the sequence.","")
       
       
       
        try
            {
            if (!ans || isNaN(ans))
               {                  
                throw new Error('That is not a number.')
               }
        ans2 = prompt("Enter the last number in the sequence.","")
            if (!ans2 || isNaN(ans2))
               {                  
                throw new Error('That is not a number. Hit F5 and re-enter')
               }
            }

        catch(errMsg)
            {
            alert(errMsg.message)
            }
        finally     
            {
                for(i = ans; i > ans2; i++)   
                {
                document.write('<tr align="center"><td>' + i + '<\/td><td>' + i*i + '<\/td><td>' + i*i*i + '<\/td><\/tr>');
                }
            }   
       
       
            // End hiding script from old browsers -->
    </script>    

JESUS CHRIST FAGGOTS
FINALLY BLOCKS ARE FOR CLEANUP
THEY EXECUTE EVEN IF THERE'S AN ERROR, WHICH IS EXACTLY WHAT YOU DON'T WANT FOR THE CODE YOU DUMPED THERE

SINCERELY,
EXPERT PROGRAMMER