Hi,

My JavaScript knowledge is very poor (I'm a layout artist(!!)) so could someone have a look at this for me and let me know what's going on.

http://www.lsi-gifts.co.uk/dev/jscalc/

The first two answer boxes work perfectly. However, I've been playing about with the third answer box and cannot get it to give the correct answer (which is 12.6 with the default values).

Can someone take a look at it for me and let me know what's going on. The formula I want to use is as follows:

(30f * (b+d) * (a + c)) / 1000

I'm not doing any of the others as the rest of the answers revolve around the same formula so sod that until I get this one right!

I look forward to your replies.

Cheers,

Scott.

It would probably be work out if you used the same equation in your javascript that you do in this post.

eval(
(calc.b.value + calc.d.value) * (calc.a.value + calc.c.value) * (30 * calc.f.value) / 1000
);

You're missing some parenthesis

eval(
( (calc.b.value + calc.d.value) * (calc.a.value + calc.c.value) * (30 * calc.f.value) )/ 1000
);

Thanks for your help but it's still throwing out the same, wrong, answer I'm afraid. It's giving out 5949.9 rather than 12.6. I admit that it makes the product look very good but it's somewhat misleading!!

Any other ideas?

Cheers,

Scott.

doh!, I got hit with the oldest one in the book.
The string arithmetic was throwing it off (gotta convert those strings to numbers).
Try this:

eval(
  (
        (Number(calc.b.value) + Number(calc.d.value))
     * (Number(calc.a.value) + Number(calc.c.value))
     * (30 * Number(calc.f.value))
  )/ 1000
);

The new lines were just added for clarity

Thank you very much! All sorted now.