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 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;
}

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  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also

Document Tags and Contributors

Last updated by: fscholz,
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