parseInt behaving different in IE and chrome [dupl

问题:

This question already has an answer here:

• How to parseInt a string with leading 0 6 answers

i have parseInt function.

for 010 as input :

output in IE : 8 output in chrome and firefox: 10

for 099 as input:

output in IE : 0 output in chrome and firefox: 99

Could someone plz help me understand this different behaviour in the browsers.. issue is in IE and it is working as expected in chrome and firefox.

Thanks in advance.

回答1:

Actually I would argue IE is doing things correctly* here . parseInt for a string starting with a 0 is treated as octal input.

To fix the problem, specify the base (in this case, you want decimal - 10):

num = parseInt(str, 10);

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* In this case "correctly" really means "traditionally". The specification has actually changed. Technically, a string starting with 0 can be treated as either octal OR decimal, depending on the implementor's whim, where decimal is now preferred:

If radix is undefined or 0 (or absent), JavaScript assumes the following:

• If the input string begins with "0", radix is eight (octal) or 10 (decimal). Exactly which radix is chosen is implementation-dependent. ECMAScript 5 specifies that 10 (decimal) is used, but not all browsers support this yet. For this reason always specify a radix when using parseInt.