Show a leading zero if a number is less than 10

Question

Possible Duplicate:
JavaScript equivalent to printf/string.format
How can I create a Zerofilled value using JavaScript?

I have a number in a variable:

var number = 5;

I need that number to be output as 05:

alert(number); // I want the alert to display 05, rather than 5.

How can I do this?

I could manually check the number and add a 0 to it as a string, but I was hoping there's a JS function that would do it?

http://stackoverflow.com/questions/1267283/how-can-i-create-a-zerofilled-value-using-javascript — stivlo, Nov 11 '11 at 05:02
See this: http://stackoverflow.com/questions/2998784/how-to-output-integers-with-leading-zeros-in-javascript — ddrace, Nov 11 '11 at 05:05

score 186 · Accepted Answer · edited Jan 20 '20 at 06:39

186

There's no built-in JavaScript function to do this, but you can write your own fairly easily:

function pad(n) {
    return (n < 10) ? ("0" + n) : n;
}

EDIT:

Meanwhile there is a native JS function that does that. See String#padStart

console.log(String(5).padStart(2, '0'));

edited Jan 20 '20 at 06:39

answered Nov 11 '11 at 05:07

Chris Fulstow

12

Or `...n < 10 && n >=0...`, so you don't end up with "0-5". – nnnnnn Nov 11 '11 at 06:21
2

Taking care of negavite upto 10 as well: function pad(n) { if (n < 10 & n >=0) return ("0" + n); if(n < 0 & n > -11) return ("-0" + Math.abs(n)); return n; } – Abs Apr 01 '14 at 09:48
1

Nice one about the `padStart()` function. – Kurt Van den Branden Jan 24 '19 at 08:05
1

FYI, according to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart Internet Explorer does not support `padStart`. – Gavin Jun 05 '19 at 08:54

Wazy · Answer 2 · 2011-11-11T05:11:30.590

12

Try this

function pad (str, max) {
  return str.length < max ? pad("0" + str, max) : str;
}

alert(pad("5", 2));

Example

Or

var number = 5;
var i;
if (number < 10) {
    alert("0"+number);
}

Example

edited Nov 11 '11 at 05:11

answered Nov 11 '11 at 05:05

Wazy

4

read his last sentence...he knows how to do that already, he was looking for a format function i believe. – mpen Nov 11 '11 at 05:07