Input field dropping 00 after decimal

Question

val = "2.";
var num = parseFloat(val).toFixed(2);

I'm using the parseFloat to turn the string into a number. Then I'm using toFixed(2) to make sure 2 zeros will be added after the decimal point. My problem is if val has a comma this gets all screwed up.

Example:

val = "2,234.";
var num = parseFloat(val).toFixed(2);

The output is 2.00.

How can I allow for the 00 to be added and the comma not to be replaced?

Val is a string to start with sorry about the confusion. it should end up outputting 2,234.00 and the first val should output 2.00

possible duplicate of [Javascript parse float is ignoring the decimals after my comma](http://stackoverflow.com/questions/7571553/javascript-parse-float-is-ignoring-the-decimals-after-my-comma) — j08691, May 01 '13 at 19:33
For the input `2,234` are you looking to get `2234.00` as output? or some other number? — Will, May 01 '13 at 19:33
Your second example is a syntax error anyway. Did you mean `"2,234."` — Matt Burland, May 01 '13 at 19:36
@MattBurland: No, it's not a syntax error. Try it. :) http://jsfiddle.net/Guffa/SfZHF/ — Guffa, May 01 '13 at 19:43
@TomSmilack: Hm... There has to be something else happening... I get `2` whe I try it, not `234`. — Guffa, May 01 '13 at 19:48
@TomSmilack: The Chrome console gives me a syntax error. Might be browser dependent. Actually scratch that - if I do `var l = 2,234.;` I get a syntax error, but `l = 2,234.;` does not. Strange. — Matt Burland, May 01 '13 at 19:49
Oops, you're right @Guffa, `val` is set to `2` and the whole line evaluates to `234` (i.e., `(val = 2,234.) == 234` is true). — Tom Smilack, May 01 '13 at 19:53
@MattBurland: With `var` it is a syntax error, because then it expects an assignment after the comma, something like `var l = 2, m = 234.;`. — Guffa, May 01 '13 at 20:01

score 0 · Answer 1 · edited Jun 20 '20 at 09:12

There is two possible reasons, depending on what your code actually is, both giving the same result.

If the code is exactly as in the question, i.e.:

val = 2,234.;

then you are using the comma operator, which takes two operands, evaluates both, then returns the value of the second one. The assignment of 2 to the variable val is the first operand, and the value 234. is the second operand. The assignment happens, then 234. is evaluated, returned by the comma operator, and discarded. The code is evaluated as:

(val = 2) , (234.);

If it's a string value, i.e.:

val = "2,234.";

then the reason is that the parseFloat function only parses characters as far as it can, and a comma is not part of the number format so it stops there and returns the 2.

Edit:

To parse the string, you have to remove the comma, parse it, and then put the comma back:

var s = parseFloat(val.replace(/,/g,'')).toFixed(2);
while (/\d{4}/.test(s)) {
  s = s.replace(/(\d{3}[,.])/,',$1');
}

Demo: http://jsfiddle.net/Guffa/KHjjh/

Good answer, I was typing mine then this one popped up! Assuming it is in fact a string "2,234." you can simply eliminate the commas with this code: `val.split(",").join("")` Or use the `.replace` function, but that requires regex so you'll probably be better off with the easier one. — Ennui, May 01 '13 at 19:43

Four_lo · Accepted Answer · 2013-05-01T20:15:44.903

0

I Believe the only way to work around this is replace the comma with an empty string. This here should work

 val = 2,234.;
 var num = parseFloat(val.replace(',', '')).toFixed(2).replace(/(\d)(?=(\d\d\d)+(?!\d))/g, "$1,");

If the val is already a string this should be the most concise way to do it using jQuery

edited May 01 '13 at 20:15

answered May 01 '13 at 19:42

Four_lo

1,150
10
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You have to make `val` a string, otherwise you can't use the `replace` method on it. – Guffa May 01 '13 at 19:45
That's the first step, but then I believe he wants the commas back in the number format. – Brian Stephens May 01 '13 at 19:45
I need to be able to replace the comma after removing it. Brian is correct in his thinking. – Chapsterj May 01 '13 at 20:05
Here is the answer var num = parseFloat(val.replace(',', '')).toFixed(2).replace(/(\d)(?=(\d\d\d)+(?!\d))/g, "$1,"); – Chapsterj May 01 '13 at 20:14
I have to vote you Four_lo as you got most of it correct I just need to do some regx at the end. Thanks – Chapsterj May 01 '13 at 20:14
thanks, Ya I was just playing with a jfiddle trying to avoid regex, but seems to be the best solution – Four_lo May 01 '13 at 20:16

Will · Answer 3 · 2013-05-01T19:54:46.670

Assuming you are using strings.

As Guffa explained parseFloat won't work once it hits the comma... So we'll just strip them out...

var val = '2,234.';

val = val.replace(',', '') // remove commas

var num = parseFloat(val).toFixed(2); // 2234.00

Now we need to put the comma back. Thanks to another answer on stack overflow we have:

// http://stackoverflow.com/questions/6392102/add-commas-to-javascript-output
var addCommas = function(nStr) {
  nStr += '';
  x = nStr.split('.');
  x1 = x[0];
  x2 = x.length > 1 ? '.' + x[1] : '';
  var rgx = /(\d+)(\d{3})/;
  while (rgx.test(x1)) {
      x1 = x1.replace(rgx, '$1' + ',' + '$2');
  }
  return x1 + x2;
};

num = addCommas(num); // "2,234.00"

Input field dropping 00 after decimal

3 Answers3

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