Name
Function.apply( ) — invoke a function as a method of an object
Availability
JavaScript 1.2; JScript 5.5; ECMAScript v3
Synopsis
function
.apply(thisobj
,args
)
Arguments
-
thisobj
The object to which
function
is to be applied. In the body of the function,thisobj
becomes the value of thethis
keyword.-
args
An array of values to be passed as arguments to
function
.
Returns
Whatever value is returned by the invocation of
function
.
Throws
-
TypeError
If this method is invoked on an object that is not a function or if this method is invoked with an
args
argument that is not an array or an Arguments object.
Description
apply( )
invokes the specified
function
as if it were a method of
thisobj
, passing it the arguments
contained in the args
array. It returns
the value returned by the function invocation. Within the body of the
function, the this
keyword refers to the
thisobj
object.
The args
argument must be an array or an
Arguments object. Use Function.call( )
instead if
you want to specify the arguments to pass to the function
individually instead of as array elements.
Example
// Apply the default Object.toString( ) method to an object that // overrides it with its own version of the method. Note no arguments. Object.prototype.toString.apply(o); // Invoke the Math.max( ) method with apply to find the largest // element in an array. Note that first argument doesn't matter // in this case. var data = [1,2,3,4,5,6,7,8]; Math.max.apply(null, data);
See Also
Get JavaScript: The Definitive Guide, Fourth Edition now with the O’Reilly learning platform.
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