I loose a penny each time I check/uncheck a box

[RoboPunk]

I am modifying an order page script so that it will add sales tax to the total. I added the function to do so and when I tested the page it looked like everything worked, but when you check a product with cents other than .00 in the price and then un-check the sales tax box &quot;Do you live in MD?&quot; the total would loose a penny. And every time after that you check and un-check the sales tax box, the total will loose a penny each time. Any help with this problem would be very appreciated.<br>The script's URL is:<br><A HREF="

http://members.aol.com/letteredge/domestic1.htm"

TARGET="_new">

http://members.aol.com/letteredge/domestic1.htm</A>

<br><br>Thank you,<br>Nathan

 

[philcha]

RoboPunk,

Since your script's fairly big and I don't feel like heavy debugging I'll offer just a few suggestions:
* the problem's probably in the fix() function which the Salestax() function calls.
* successive multiplication and division on the same number (the total sales value) always has a risk of rounding error. It's safer to work out the total from the raw data each time. If that's not possible, keep separate pre-tax and post-tax figures, and work out the post-tax figure afresh from the pre-tax figure every time the &quot;Maryland&quot; checkbox changes.