Delete many decimal

Question

Hello I have problem with a simple function in JavaScript if I add 0.0001 + 0.0001 + 0.0001 i have 0.0002999999999999999999 I don't know why because it's simple Number(x) + Number(y).

With php I use this function and it's work perfectly

$number = number_format($number, 10, '.', '');
$number = rtrim(rtrim($number, '0'), '.');

What is the equivalent of this script PHP in Javascript?

http://stackoverflow.com/questions/588004/is-floating-point-math-broken — epascarello, Apr 10 '15 at 13:35
What did you try so far in javascript as for this equivalent? — doldt, Apr 10 '15 at 13:35
[`Number.prototype.toFixed`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed) — Pointy, Apr 10 '15 at 13:35

score 2 · Accepted Answer · answered Apr 10 '15 at 13:41

Use toFixed to convert it to a string with some decimal places shaved off, and then convert it back to a number.

+(0.0001 + 0.0001).toFixed(12) // 0.0002

It looks like IE's toFixed has some weird behavior, so if you need to support IE something like this might be better:

Math.round((0.0001 + 0.0001) * 1e12) / 1e12

score 1 · Answer 2 · answered Apr 10 '15 at 13:39

You're running into errors with floating point storage of numbers which isn't perfect. If you know exactly what precision you need, you can use the toFixed function to display the number as a string:

var x = 0.0001 + 0.0001 + 0.0001;
console.log(x.toFixed(4));
// "0.0003"

score 1 · Answer 3 · answered Apr 10 '15 at 13:40

1

Try like this using toFixed():

var x = 0.0001 + 0.0001 + 0.0001;
alert(x.toFixed(4));

JSFIDDLE DEMO

Also note that Javascript uses 64 bit floating point representation and follow IEEE 754 standard for float.

answered Apr 10 '15 at 13:40

Rahul Tripathi

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score 1 · Answer 4 · edited Apr 10 '15 at 14:00

1

You may take help of toFixed to convert it to string and then convert it back to a number.

+(0.0001 + 0.0001).toFixed(12) // 0.0002

In case of IE you may write like this

Math.round((0.0001 + 0.0001) * 1e12) / 1e12

edited Apr 10 '15 at 14:00

Rahul Tripathi

168,305
31
280
331

answered Apr 10 '15 at 13:44

Shayan Ghosh

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14

Delete many decimal

4 Answers4