LANGUAGE » JAVASCRIPT

Number

Last updated:
Reference:developer.mozilla.org

Basic usage ​

javascript
mynum = 1000;        // Decimal notation
mynum = 1e3;         // Exponential notation (same as 1 * 10^3 = 1000)
mynum = 0xff;        // Hexadecimal notation
mynum = 0b11111111;  // Binary notation

Convert from string ​

Both integer and float are Number.

javascript
Number.parseInt('10');
Number.parseFloat('3.1416');

If the conversion fails, NaN is returned.

javascript
isNaN(myVar);

Rounding ​

To the nearest integer:

javascript
Math.round(0.9);
// 1

With the specified number of decimal places (string is returned):

javascript
3.78932.toFixed(2);
// '3.79'