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The arguments.length property contains the number of arguments passed to the function.

Syntax

arguments.length

Description

The arguments.length property provides the number of arguments actually passed to a function. This can be more or less than the defined parameter's count (see Function.length).

Examples

Using arguments.length

In this example we define a function that can add two or more numbers together.

function adder(base /*, n2, ... */) {
  base = Number(base);
  for (var i = 1; i < arguments.length; i++) {
    base += Number(arguments[i]);
  }
  return base;
}

Note the difference between Function.length and arguments.length

Specifications

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.1
ECMAScript 5.1 (ECMA-262)
The definition of 'Arguments Object' in that specification.
Standard  
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Arguments Exotic Objects' in that specification.
Standard  
ECMAScript Latest Draft (ECMA-262)
The definition of 'Arguments Exotic Objects' in that specification.
Living Standard  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes Yes Yes Yes Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support Yes Yes Yes Yes Yes Yes Yes

See also

文件標籤與貢獻者

 最近更新: fscholz,