parseInt(expression:String [, radix:Number]) : Number

Converts a string to an integer. If the specified string in the parameters cannot be converted to a number, the function returns NaN. Strings beginning with 0x are interpreted as hexadecimal numbers. Integers beginning with 0 or specifying a radix of 8 are interpreted as octal numbers. White space preceding valid integers is ignored, as are trailing nonnumeric characters.

Parameters

expression:String - A string to convert to an integer.

radix:Number [optional] - An integer representing the radix (base) of the number to parse. Legal values are from 2 to 36.

Returns

Number - A number or NaN (not a number).

Example

The examples in this section use the parseInt() function to evaluate various types of numbers.

The following example returns 3:

parseInt("3.5")

The following example returns NaN:

parseInt("bar")

The following example returns 4:

parseInt("4foo")

The following example shows a hexadecimal conversion that returns 1016:

parseInt("0x3F8")

The following example shows a hexadecimal conversion using the optional radix parameter that returns 1000:

parseInt("3E8", 16)

The following example shows a binary conversion and returns 10, which is the decimal representation of the binary 1010:

parseInt("1010", 2)

The following examples show octal number parsing and return 511, which is the decimal representation of the octal 777:

parseInt("0777")
parseInt("777", 8)

See also

NaN constant, parseFloat function