parseInt（）和octal - 哪些浏览器支持它？

Question

The javascript parseInt function evaluates '010' as decimal 10, not octal 8, in all of the browsers I've tried - relatively recent versions of Chrome, Firefox and IE - which is what you'd expect since this has been deprecated for a long time.

But I've got some code that isn't specifying the radix and I'm wondering if someone running an old browser could find a bug. Has anyone compiled a list of which browsers/versions will parse octal? How common is it?

Answer 1

ECMAScript 3 said

When radix is 0 or undefined and the string's number begins with a 0 digit not followed by an x or X , then the implementation may, at its discretion, interpret the number either as being octal or as being decimal. Implementations are encouraged to interpret numbers in this case as being decimal.

ECMAScript 5 says

If radix is undefined or 0, it is assumed to be 10 except when the number begins with the character pairs 0x or 0X , in which case a radix of 16 is assumed.

Therefore, all ES5 compliant implementations will parse as decimal and not as octal.

Answer 2

ECMAScript 5 forbids parsing such (unspecified radix) strings as octal. This means IE9 and above will not have a problem (nor will most other browsers - as shown here )

I'd worry about IE8 in this case, as it's possibly still converting to octal given the leading zero and no radix. (This conversion was only discouraged, not forbidden, in ECMAScript 3 - see MDN explanation .)