Javascript string to integer

JavaScript parseInt() Function

Definition and Usage

The parseInt() function parses a string and returns an integer.

The radix parameter is used to specify which numeral system to be used, for example, a radix of 16 (hexadecimal) indicates that the number in the string should be parsed from a hexadecimal number to a decimal number.

If the radix parameter is omitted, JavaScript assumes the following:

• If the string begins with "0x", the radix is 16 (hexadecimal)
• If the string begins with "0", the radix is 8 (octal). This feature is deprecated
• If the string begins with any other value, the radix is 10 (decimal)

Syntax

Javascript string to integer examples:

Examples (comments in each line give the conversion results):

parseFloat('1.45kg') // 1.45
parseFloat('77.3') // 77.3
parseFloat('077.3') // 77.3
parseFloat('0x77.3') // 0
parseFloat('.3') // 0.3
parseFloat('0.1e6') // 100000
parseInt('123.45') // 123
parseInt('77') // 77
parseInt('077',10) // 77
parseInt('77',8) // 63 (= 7 + 7*8)
parseInt('077') // 63 (= 7 + 7*8)
parseInt('77',16) // 119 (= 7 + 7*16)
parseInt('0x77') // 119 (= 7 + 7*16)
parseInt('099') // 0 (9 is not an octal digit)
parseInt('99',8) // 0 or NaN, depending on the platform
parseInt('0.1e6') // 0
parseInt('ZZ',36) // 1295 (= 35 + 35*36)

Tips and Notes

Note: Only the first number in the string is returned!

Note: Leading and trailing spaces are allowed.

Note: If the first character cannot be converted to a number, parseInt() returns NaN.