Question

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Workarounds for JavaScript parseInt octal bug

It seems as though leading zeroes should just be ignored when parsing for an Int. What is the rationale behind this?

Answer 1

Because it is parsed as an octal number, and not decimal.
From MDC:

• If the input string begins with “0x” or “0X”, radix is 16
  (hexadecimal).
• 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.
• If the input
  string begins with any other value, the radix is 10 (decimal).

To force it to parse as Decimal, just supply 10 as your second argument (base).

var i = parseInt(012,10);