JavaScript parseInt()Function

JavaScript Global Functions

Definition and Usage

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

When the radix parameter is 0, or when this parameter is not set, parseInt() determines the base of the number based on the string.

When the radix parameter is omitted, JavaScript defaults the number's base as follows:

• If the string begins with "0x", parseInt() parses the rest of the string as a hexadecimal integer.
• If the string begins with 0, then ECMAScript v3 allows an implementation of parseInt() to parse the following characters as octal or hexadecimal numbers.
• If the string begins with a number from 1 to 9, parseInt() will parse it as a decimal integer.

Syntax

Browser Support

All major browsers support the parseInt() function

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 of the string cannot be converted to a number, parseInt() returns NaN.

Note:When strings start with "0", older browsers default to an octal base. In ECMAScript 5, the default is a decimal base.

Examples

Note:Older browsers use an older version of ECMAScript (ECMAScript versions earlier than ECMAScript 5 default to octal when a string starts with "0", while ECMAScript 5 uses decimal), so parsing ("010") will output 8.

JavaScript Global Functions