arguments Object (JavaScript)

2017-1-18 1 minutes to read Contributors

An object representing the arguments to the currently executing function, and the functions that called it.

Syntax

[function.]arguments[n]

Parameters

function
Optional. The name of the currently executing Function object.

n
Required. The zero-based index to argument values passed to the Function object.

Remarks

You cannot explicitly create an arguments object. The arguments object only becomes available when a function begins execution. The arguments object of the function is not an array, but the individual arguments are accessed the same way array elements are accessed. The index n is actually a reference to one of the 0 n properties of the arguments object.

Example

The following example illustrates the use of the arguments object.

function ArgTest(a, b)  
{  
   var s = "";  

   s += "Expected Arguments: " + ArgTest.length;  
   s += "<br />";  
   s += "Passed Arguments: " + arguments.length;  
   s += "<br />";  

   s += "The individual arguments are: "  
   for (n = 0; n < arguments.length; n++)  
   {  
      s += ArgTest.arguments[n];  
      s += " ";  
   }  

   document.write(s);  
}  

ArgTest(1, 2, "hello", new Date())  

// Output:  
// Expected Arguments: 2  
// Passed Arguments: 4  
// The individual arguments are: 1 2 hello Tues Jan 8 08:27:09 PST 20xx

Requirements

Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards, Internet Explorer 11 standards. Also supported in Store apps (Windows 8 and Windows Phone 8.1). See Version Information.