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In C# whenever I wanted to print two digit numbers I've used

int digit=1; Console.Write(digit.ToString("00"));

How can I do the same action in Javascript ?
Thanks

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4 Answers 4

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c# digit.toString("00") appends one zero to the left of digit (left padding). In javascript I use this functon for that:

function zeroPad(nr,base){ var len = (String(base).length - String(nr).length)+1; return len > 0? new Array(len).join('0')+nr : nr; } zeroPad(1,10); //=> 01 zeroPad(1,100); //=> 001 zeroPad(1,1000); //=> 0001

You can also rewrite it as an extention to Number:

Number.prototype.zeroPad = Number.prototype.zeroPad || function(base){ var nr = this, len = (String(base).length - String(nr).length)+1; return len > 0? new Array(len).join('0')+nr : nr; }; //usage: (1).zeroPad(10); //=> 01 (1).zeroPad(100); //=> 001 (1).zeroPad(1000); //=> 0001

[edit oct. 2021]

A static es20xx Number method, also suitable for negative numbers.

Number.padLeft = (nr, len = 2, padChr = `0`) => `${nr < 0 ? `-` : ``}${`${Math.abs(nr)}`.padStart(len, padChr)}`; console.log(Number.padLeft(3)); console.log(Number.padLeft(284, 5)); console.log(Number.padLeft(-32, 12)); console.log(Number.padLeft(-0)); // Note: -0 is not < 0

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2 Comments

It should be noted that this won't work with negative numbers, i.e. it's made to work with positive numbers only. (Only saying this because I was looking for a similar formatter that deals with neg numbers as well.)
I would like to point out that, 8 years later, this is what padStart does, which major browsers support. developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
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I usually just do something like ("00000000"+nr).slice(-base) where nr is the number and base is the number of digits you want to end up with.

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One way would be to download sprintf for javascript and writing something like this:

int i = 1; string s = sprintf("%02d", i); document.write(s); // Prints "01"
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-1 
var num =10 document.write(num);

But if your question is to use two digit numbers twice then you can use this

var num1 = 10; var num2 = 20; var resultStr = string.concat(num1,num2); document.write(resultStr); ... Result: 1020

if you want a space in between,

var resultStr = string.concat(num1,"",num2);

Hope this helps...

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5 Comments

I think was op wants is padding the number if it's < 10, so 1 becomes string 01 or 001
This wont help, as it doesn't address the problem of String formatting. (e.g. the op wants to have something like i=1 ==> "01")
Nope, you didn't understand. Your answer has nothing to do with string padding
@codemonkey: before your first comment came, I was actually modifying the code so couldn't look at it and after saving, the page updated with your comment. So it's not that I have not understood. I have understood it properly. Thanks anyways....
You still haven't understood it. Your answer still has nothing to do with STRING PADDING. Op was looking for a way to fill out a string with zeros to ensure a fixed length. For instance, 1 becomes "001"

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