perl / ifram / javascript question

[Madison Kelly]

Andrej Marjan wrote:
> Madison Kelly wrote:
>> Hi all,
>>
>>   I've got a thing I want to do with my web app that I know is 
>> possible but can't for the life of me figure out... I've googled this 
>> do death but am probably stumbling over something really simple.
>>
>>   Anyway, I want to use perl to round a number (for now; later want to 
>> submit a form without reloading the whole page).
>>
>>   So I'd like to be able to have a javascript function pass a couple 
>> variables to a perl script (ie: 
>> 'http://foo.com/cgi-bin/script?num=<real_number>&precision=<precision>'). 
>> Then, once the perl script does it's magic, load the numbers into 
>> hidden form fields via an iframe for the calling script to read).
> 
> Well you could just do it in javascript, e.g. 1.563532.toPrecision(3) == 
> "1.56"
> 
> Do you have a particular reason for wanting to do the rounding server-side?
> 
> I don't know if there's a cleverer way to do it in Perl, but sprintf 
> will do the trick, e.g. sprintf("%.2f", 1.5678).

In this case the problem is Javascript is not very good at rounding. 
This is more of an issue because this is a financial program and a 
rounding error could cost me money or, worse, charge a customer too much 
money. Perhaps a penny here or there, but regardless, it would make me 
look unprofessional.

That said, perl isn't perfect either but it is a lot easier to account 
for it's short comings. I can't remember exactly how it was done but it 
wasn't with sprintf alone... I wrote it for another program so I need to 
write a new function from scratch but I know it can be done a lot more 
reliably.

The need to tie it in with the Javascript is that as I or a user adds 
items to an invoice I use JS to calculate a running subtotal/taxes/total 
at the bottom. I have always planned to run the final calculations 
through perl, so this would save me doing it twice, too.

Thanks for the reply!

Madi
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