arguments.length

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;
}

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 2017 Draft (ECMA-262) The definition of 'Arguments Exotic Objects' in that specification.	Draft

Browser compatibility

See also

• Function
• Function.length