Easy Tutorial
❮ Prop Audio Playbackrate Met Win Atob ❯

JavaScript parseInt() Function


Definition and Usage

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

When the radix parameter is 0 or not provided, parseInt() will determine the base of the number from the string.

When the radix parameter is omitted, JavaScript defaults to the following bases:

Syntax

Parameter Description
string Required. The string to be parsed.
radix Optional. The base of the number to be parsed, which ranges from 2 to 36.

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: Older browsers default to an octal base when the string starts with "0". ECMAScript 5 defaults to a decimal base.


Examples

We will use parseInt() to parse different strings:

document.write(parseInt("10") + "<br>");
document.write(parseInt("10.33") + "<br>");
document.write(parseInt("34 45 66") + "<br>");
document.write(parseInt(" 60 ") + "<br>");
document.write(parseInt("40 years") + "<br>");
document.write(parseInt("He was 40") + "<br>");

document.write("<br>");
document.write(parseInt("10", 10) + "<br>");
document.write(parseInt("010") + "<br>");
document.write(parseInt("10", 8) + "<br>");
document.write(parseInt("0x10") + "<br>");
document.write(parseInt("10", 16) + "<br>");

The above examples output the following results:

document.write(parseInt("10") + "<br>");
document.write(parseInt("10.33") + "<br>");
document.write(parseInt("34 45 66") + "<br>");
document.write(parseInt(" 60 ") + "<br>");
document.write(parseInt("40 years") + "<br>");
document.write(parseInt("He was 40") + "<br>");
document.write("<br>");
document.write(parseInt("10", 10) + "<br>");
document.write(parseInt("010") + "<br>");
document.write(parseInt("10", 8) + "<br>");
document.write(parseInt("0x10") + "<br>");
document.write(parseInt("10", 16) + "<br>");

Note: Older browsers, using older versions of ECMAScript (before ECMAScript 5), default to an octal base when the string starts with "0". ECMAScript 5 defaults to a decimal base.

❮ Prop Audio Playbackrate Met Win Atob ❯