0888 // 888 parsed as decimal
0777 // parsed as octal in non-strict mode (511 in decimal)
Note that decimal literals can start with a zero ( 0 ) followed by another decimal digit, but if every digit after the leading 0 is smaller than 8, the number gets parsed as an octal number.
so
01.
seems to be a big NO in javascript
as octal numbers can not be floating point.