If the input string begins with "0", radix is eight (octal). This feature is non-standard, and some implementations deliberately do not support it (instead using the radix 10). For this reason always specify a radix when using parseInt.

While the radix parameter is optional, always specify it to eliminate reader confusion and to guarantee predictable behavior. Different implementations produce different results when a radix is not specified. [1]

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[1]: https://developer.mozilla.org/en/JavaScript/Reference/Global...