How to parseInt a string with leading 0

Question

How to parseInt "09" into 9 ?

Gabe Moothart · Accepted Answer · 2009-10-09 17:49:19Z

57

include the radix:

parseInt("09", 10);

answered Oct 9, 2009 at 17:49

Gabe Moothart

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codeulike · Accepted Answer · 2011-06-08 15:50:30Z

12

This has been driving me nuts -parseInt("02") works but not parseInt("09").

As others have said, the solution is to specify base 10:

parseInt("09", 10);

There's a good explanation for this behaviour here

... In Javascript numbers starting with zero are considered octal and there's no 08 or 09 in octal, hence the problem.

answered Jun 8, 2011 at 15:50

codeulike

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Comments

Kieran Pilkington · Accepted Answer · 2011-01-17 22:24:27Z

5

You can also do:

Number('09') => 9

This returns the integer 9 on IE7, IE8, FF3, FF4, and Chrome 10.

answered Jan 17, 2011 at 22:24

Kieran Pilkington

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TDot · Accepted Answer · 2012-10-23 19:34:20Z

5

Re-implement the existing parseInt so that if it is called with one argument then "10" is automatically included as the second argument.

(function(){
  var oldParseInt = parseInt;
  parseInt = function(){
    if(arguments.length == 1)
    {
      return oldParseInt(arguments[0], 10);    
    }
    else
    {
      return oldParseInt.apply(this, arguments);
    }
  }
})();

answered Oct 23, 2012 at 19:34

TDot

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JCasso · Accepted Answer · 2009-10-09 18:03:46Z

2

parseInt("09",10);

returns 9 here.

It is odd.

alert(parseInt("09")); // shows 9. (tested with Opera 10)

edited Oct 9, 2009 at 18:03

answered Oct 9, 2009 at 17:54

JCasso

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5 Comments

JCasso Over a year ago

@JonH: Right. Thanks for warning. Since he wrote string instead of String I was mistaken.

JonH Over a year ago

Depending on the browser and version parseInt("09") can return 0. It is a bug.

JCasso Over a year ago

@JonH: can you please check this: w3schools.com/jsref/jsref_parseInt.asp document.write(parseInt("010") also displays 10 here.

Matthew Crumley Over a year ago

@JonH: It's not actually a bug. ECMAScript allows implementations to treat numbers with leading zeros as octal. Some implementations do, and some don't.

RobG Over a year ago

@MatthewCrumley—an old comment but what the heck - ES5 removes that behaviour, so compliant browsers should treat parseInt('08') as base 10.

Praveen · Accepted Answer · 2013-08-27 12:30:28Z

2

parseInt("09", 10);

or

parseInt(parseFloat("09"));

edited Aug 27, 2013 at 12:30

Praveen

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answered Oct 9, 2009 at 17:50

JonH

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