parseInt Function (JavaScript)

numString

Required. A string to convert into a number.

radix

Optional. A value between 2 and 36 indicating the base of the number contained in numString. If this argument is not supplied, strings with a prefix of '0x' are considered hexadecimal. All other strings are considered decimal.

The parseInt function returns an integer value equal to the number contained in numString. If no prefix of numString can be successfully parsed into an integer, NaN (not a number) is returned.

parseInt("abc")     // Returns NaN.
parseInt("12abc")   // Returns 12.

You can test for NaN using the isNaN function.

Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards. See Version Information.

Applies To: Global Object (JavaScript)

Note
Starting in Internet Explorer 9 standards mode, the parseInt function does not treat a string that has a prefix of '0' as octal. When you are not using the parseInt function, however, strings with a prefix of '0' can still be interpreted as octal. See Data Types (JavaScript) for information about octal integers.

Reference