Javascript [Electronic resources] : The Definitive Guide (4th Edition) نسخه متنی

7.3 Function Scope: The Call Object

As
described in Chapter 4, the body of a JavaScript
function executes in a local scope that differs from the global
scope. This new scope is created by adding the call object to the
front of the scope chain. Since the call object is part of the scope
chain, any properties of this object are accessible as variables
within the body of the function. Local
variables
declared with the var statement are created as
properties of this object; the parameters of the function are also
made available as properties of the object.

In
addition to local variables and parameters, the call object defines
one special property named arguments. This
property refers to another special object known as the Arguments
object, which is discussed in the next section. Because the
arguments property is a property of the call
object, it has exactly the same status as local variables and
function parameters. For this reason, the

identifier
arguments should be considered a reserved word and
should not be used as a variable or parameter name.