翻譯不完整。請協助 翻譯此英文文件

Math.abs() 函式會回傳一個數字的絕對值,即為:

Math.abs(x)=|x|={xifx>00ifx=0-xifx<0{\mathtt{\operatorname{Math.abs}(x)}} = {|x|} = \begin{cases} x & \text{if} \quad x \geq 0 \\ x & \text{if} \quad x < 0 \end{cases}

語法

Math.abs(x)

參數

x
一個數字。

回傳值

給定數字的絕對值。

描述

Because abs() is a static method of Math, you always use it as Math.abs(), rather than as a method of a Math object you created (Math is not a constructor).

範例

Math.abs() 的行為

Passing an empty object, an array with more than one member, a non-numeric string or undefined/empty variable returns NaN. Passing null, an empty string or an empty array returns 0.

Math.abs('-1');     // 1
Math.abs(-2);       // 2
Math.abs(null);     // 0
Math.abs('');       // 0
Math.abs([]);       // 0
Math.abs([2]);      // 2
Math.abs([1,2]);    // NaN
Math.abs({});       // NaN
Math.abs('string'); // NaN
Math.abs();         // NaN

規範

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262)
The definition of 'Math.abs' in that specification.
Standard  
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.abs' in that specification.
Standard  
ECMAScript Latest Draft (ECMA-262)
The definition of 'Math.abs' in that specification.
Draft  

瀏覽器相容性

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes Yes1 Yes Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes4 Yes Yes Yes

參見

文件標籤與貢獻者

 此頁面的貢獻者: jackblackevo
 最近更新: jackblackevo,