Possible Duplicate:
Leading zero in javascript
Given you have the following JavaScript snippet:
<script>
var x = 013;
console.log(x);
</script>
Why is it that Firebug prints 11?
Asked
Active
Viewed 94 times
0
Community
- 1
- 1
Stephan Kristyn
- 15,015
- 14
- 88
- 147
-
does it interpret that as octal? – dbeer Oct 17 '11 at 21:36
-
4Read: https://developer.mozilla.org/en/JavaScript/Guide/Values%2c_Variables%2c_and_Literals#Integers – Felix Kling Oct 17 '11 at 21:37
-
The leading 0 means it's in [Octal](http://en.wikipedia.org/wiki/Octal). – wkl Oct 17 '11 at 21:37
6 Answers
4
JavaScript supports the same convention for numeric constants as C and Java (et al), so the leading zero makes that an octal constant. ("13" in base 8 is 8 + 3, or 11.)
Pointy
- 405,095
- 59
- 585
- 614
-
-
-
-
-
1@karim79: Yes you are, but you were a mega-rockstar when you were Simpsonized. ;) – user113716 Oct 17 '11 at 21:43
-
The Red Hot Chili Peppers are old too and still rock stars.... at least for me ;) You are never to old to be a rock star! – Felix Kling Oct 17 '11 at 21:43
-
@Ӫ_._Ӫ - I de-simponified myself in the hope that a more personal photo would gain me more rep. How wrong I was. :( – karim79 Oct 17 '11 at 21:45
-
-
-
2
Because you've specified an octal number, but it displays its decimal representation.
user113716
- 318,772
- 63
- 451
- 440
1
It's interpreting it as octal. Any number that begins in zero is interpreted as an octal (base 8) literal, and octal 13 = 8*1+3 = 11 decimal.
Also, good title.
Dan
- 10,531
- 2
- 36
- 55
1
It is being interpreted as base 8. And 013 in base 8 is 11 decimal.
In javascript, constant numbers that begin with 0dd or -0dd and are not 0xdd or -0xdd are interpreted as octal (base 8).
You can see it described in the ECMAScript specification on page 231.
jfriend00
- 683,504
- 96
- 985
- 979
1
013 is an octal constant - it's interpreted in base 8. 1·8 + 3·1 = 8 + 3 = 11
millimoose
- 39,073
- 9
- 82
- 134