Problem with calculation in javascript 2

[Petal]

Hi

I have made a simple calculator. It works almost as it should except with multiplying with decimals.
When I try to multiply: 0.1*2.8 i got the result 0.27999999999999997 . It should be 2.8.

Here is my code:
function regnut() {
fotm.maks.value=0.1*2.8;
}

Have anybody hade a similar problem?

Jørn Arild Andenæs
jaa@jaa.no

 

[Petal]

I fined the solution by myself. I used:

maks.value=Math.round((0,1*2,8)*1000)/1000;

Jørn Arild Andenæs
jaa@jaa.no

 

[scottcm]

It has to do with how decimals are stored. Their stored as a whole number and a separate fractional number. Unfortunately some numbers can't be properly represented. Kind of like 1/3. Writing .3333 is not accurate but it is a close approximation.

Take a look in a reference manual - there may be a function to correct for this inherent problem. Another way is to use rounding. BTW, this is not a problem with JavaScript per se. Every language I've ever used has this problem to some degree or another. It all comes down to how they choose to store numbers, but with any scheme there will always be some measure of precision loss.

Scott

 

[Boomerang]

That gives me a zero ???

In javascript 1.5 you can use:

maks.value=(0.1*2.8).toFixed(2);

Hope this helps,
Erik

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