Number.prototype.toString() - JavaScript 编辑

The toString() method returns a string representing the specified Number object.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

numObj.toString([radix])

Parameters

radix Optional

An integer in the range 2 through 36 specifying the base to use for representing numeric values.

Return value

A string representing the specified Number object.

Exceptions

RangeError

If toString() is given a radix less than 2 or greater than 36, a RangeError is thrown.

Description

The Number object overrides the toString() method of the Object object. (It does not inherit Object.prototype.toString()). For Number objects, the toString() method returns a string representation of the object in the specified radix.

The toString() method parses its first argument, and attempts to return a string representation in the specified radix (base). For radices above 10, the letters of the alphabet indicate numerals greater than 9. For example, for hexadecimal numbers (base 16), a through f are used.

If the radix is not specified, the preferred radix is assumed to be 10.

If the numObj is negative, the sign is preserved. This is the case even if the radix is 2; the string returned is the positive binary representation of the numObj preceded by a - sign, not the two's complement of the numObj.

If the numObj is not a whole number, the 'dot' sign is used to separate the decimal places.

Examples

Using toString

let count = 10

console.log(count.toString())    // displays '10'
console.log((17).toString())     // displays '17'
console.log((17.2).toString())   // displays '17.2'

let x = 6

console.log(x.toString(2))       // displays '110'
console.log((254).toString(16))  // displays 'fe'

console.log((-10).toString(2))   // displays '-1010'
console.log((-0xff).toString(2)) // displays '-11111111'

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'Number.prototype.tostring' in that specification.

Browser compatibility

BCD tables only load in the browser

See also

• Number.prototype.toFixed()
• Number.prototype.toExponential()
• Number.prototype.toPrecision()