Question

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Javascript parseInt() with leading zeros

rated 0 times [ 8] [ 4] / answers: 1 / hits: 73768 / 13 Years ago, fri, january 6, 2012, 12:00:00

Javascript's parseInt function does not seem to completely work.

parseInt(01) returns 1

parseInt(02) returns 2

parseInt(03) returns 3

parseInt(04) returns 4

parseInt(05) returns 5

parseInt(06) returns 6

parseInt(07) returns 7

parseInt(08) returns 0

parseInt(09) returns 0

You can't explain that. Give it a try. (jsFiddle)

Edit Since this question was asked and answered, the feature of defaulting to octal radix has been deprecated. [1] [2]

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kennedim

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1 Year ago

answered 13 Years ago kamronr · Accepted Answer

This is because if a number starts with a '0', it's treated as base 8 (octal).

You can force the base by passing the base as the 2nd parameter.

parseInt(09, 10) // 9

According to the docs, the 2nd parameter is optional, but it's not always assumed to be 10, as you can see from your example.