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• 句法
• 描述
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

toFixed() method formats a number using fixed-point notation.

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.

句法

numObj.toFixed([digits])
					

参数

digits 可选

The number of digits to appear after the decimal point; this may be a value between 0 and 20 , inclusive, and implementations may optionally support a larger range of values. If this argument is omitted, it is treated as 0 .

返回值

A string representing the given number using fixed-point notation.

异常

RangeError

若 digits is too small or too large. Values between 0 and 100 , inclusive, will not cause a RangeError . Implementations are allowed to support larger and smaller values as chosen.

TypeError

If this method is invoked on an object that is not a Number .

描述

toFixed() returns a string representation of numObj that does not use exponential notation and has exactly digits digits after the decimal place. The number is rounded if necessary, and the fractional part is padded with zeros if necessary so that it has the specified length. If the absolute value of numObj is greater or equal to 1e+21 , this method simply calls Number.prototype.toString() and returns a string in exponential notation.

警告： Floating point numbers cannot represent all decimals precisely in binary. This can lead to unexpected results, such as 0.1 + 0.2 === 0.3 returning false .

范例

使用 toFixed

let numObj = 12345.6789
numObj.toFixed()       // Returns '12346': note rounding, no fractional part
numObj.toFixed(1)      // Returns '12345.7': note rounding
numObj.toFixed(6)      // Returns '12345.678900': note added zeros
(1.23e+20).toFixed(2)  // Returns '123000000000000000000.00'
(1.23e-10).toFixed(2)  // Returns '0.00'
2.34.toFixed(1)        // Returns '2.3'
2.35.toFixed(1)        // Returns '2.4'. Note it rounds up
2.55.toFixed(1)        // Returns '2.5'. Note it rounds down - see warning above
-2.34.toFixed(1)       // Returns -2.3 (due to operator precedence, negative number literals don't return a string...)
(-2.34).toFixed(1)     // Returns '-2.3'
					

规范

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

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

更新 GitHub 上的兼容性数据

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
toFixed	Chrome 1	Edge 12	Firefox 1	IE 5.5	Opera 7	Safari 2	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100

图例

完整支持

完整支持

另请参阅

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

元数据

• 最后修改： Jan 15, 2020

相关话题

1. 标准内置对象
2. Number
3. 特性
   1. Number.EPSILON
   2. Number.MAX_SAFE_INTEGER
   3. Number.MAX_VALUE
   4. Number.MIN_SAFE_INTEGER
   5. Number.MIN_VALUE
   6. Number.NEGATIVE_INFINITY
   7. Number.NaN
   8. Number.POSITIVE_INFINITY
4. 方法
   1. Number.isFinite()
   2. Number.isInteger()
   3. Number.isNaN()
   4. Number.isSafeInteger()
   5. Number.parseFloat()
   6. Number.parseInt()
   7. Number.prototype.toExponential()
   8. Number.prototype.toFixed()
   9. Number.prototype.toLocaleString()
   10. Number.prototype.toPrecision()
   11. Number.prototype.toSource()
   12. Number.prototype.toString()
   13. Number.prototype.valueOf()
5. 继承：
6. Function
7. 特性
   1. Function.arguments
   2. Function.caller
   3. Function.displayName
   4. Function.length
   5. Function.name
8. 方法
   1. Function.prototype.apply()
   2. Function.prototype.bind()
   3. Function.prototype.call()
   4. Function.prototype.toSource()
   5. Function.prototype.toString()
9. Object
10. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
11. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()