How to Get number with 2 decimal and not rounding using javascript?

Question

How to Get number with 2 decimal and not rounding using javascript ?

i try

http://jsfiddle.net/3AaAx/31/

var i = "1234.666";
var xxx = Math.floor(i * 100) / 100
alert(xxx);

AND

http://jsfiddle.net/3AaAx/29/

var i = "1234.666";

function myToFixed(i, digits) {
    var pow = Math.pow(10, digits);

    return Math.floor(i * pow) / pow;
}
var xxx = myToFixed(i, 2)
alert(xxx);

it's work.

But when i declare var i = "1234"; i want to get "1234.00"

http://jsfiddle.net/3AaAx/30/

http://jsfiddle.net/3AaAx/32/

How to do that ?

Answer 1

Not rounding is an unusual requirement, and it's too bad because if you were okay with rounding, you could just use toFixed :

var num = 1234.5678;
snippet.log(num.toFixed(2)); // "1234.57" -- note the rounding!

 var num = 1234.5678; snippet.log(num.toFixed(2)); // "1234.57" -- note the rounding! 

 <!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 --> <script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script> 

(And no, you can't just do .toFixed(3) and then chop off the last digit; rounding doesn't necessarily only change the last digit, consider using toFixed(3) on 1111.9999 , which gives you 1112.000 . Just chopping off the last digit of that still gives you a rounded result.)

To do it without rounding, I don't think there's much available but brute force:

// Assumes `digits` is never more than 20
function toFixedNoRounding(num, digits) {
  var parts = String(num).split('.');
  if (digits <= 0) {
    return parts[0];
  }
  var fractional = (parts[1] || "0") + "000000000000000000000";
  return parts[0] + "." + fractional.substring(0, digits);
}

 // Assumes `digits` is never more than 20 function toFixedNoRounding(num, digits) { var parts = String(num).split('.'); if (digits <= 0) { return parts[0]; } var fractional = (parts[1] || "0") + "000000000000000000000"; return parts[0] + "." + fractional.substring(0, digits); } var num, notRounded; num = 1234; notRounded = toFixedNoRounding(num, 2); snippet.log(num + " => " + notRounded); num = 1234.5678; notRounded = toFixedNoRounding(num, 2); snippet.log(num + " => " + notRounded); num = 1234.1; notRounded = toFixedNoRounding(num, 2); snippet.log(num + " => " + notRounded); num = 1234.999999; notRounded = toFixedNoRounding(num, 2); snippet.log(num + " => " + notRounded); 

 <!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 --> <script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script> 

Or you can use indexOf , but it seems a lot clunkier:

// Assumes `digits` is never more than 20
function toFixedNoRounding(num, digits) {
  var str = String(num);
  var n = str.indexOf(".") + 1;
  if (n === 0) {
    str += ".";
    n = str.length;
  }
  n = digits <= 0 ? n - 1 : n + digits;
  if (str.length !== n) {
    str = (str + "00000000000000000000").substring(0, n);
  }
  return str;
}

 // Assumes `digits` is never more than 20 function toFixedNoRounding(num, digits) { var str = String(num); var n = str.indexOf(".") + 1; if (n === 0) { str += "."; n = str.length; } n = digits <= 0 ? n - 1 : n + digits; if (str.length !== n) { str = (str + "00000000000000000000").substring(0, n); } return str; } var num, notRounded; num = 1234; notRounded = toFixedNoRounding(num, 2); snippet.log(num + " => " + notRounded); num = 1234.5678; notRounded = toFixedNoRounding(num, 2); snippet.log(num + " => " + notRounded); num = 1234.1; notRounded = toFixedNoRounding(num, 2); snippet.log(num + " => " + notRounded); num = 1234.999999; notRounded = toFixedNoRounding(num, 2); snippet.log(num + " => " + notRounded); 

 <!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 --> <script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script> 

Answer 2

  var y = "1234.045";
  var s = number_with_2_decimal(y);
  alert(s);

  function number_with_2_decimal(a) {
  var x = Math.floor(a * 100) * 0.01;
  var str = String(x);
  var n = str.indexOf('.');
  if (n === -1) {
       str += '.00';
  };
  return str;
  }