JavaScript: The Definitive Guide, Fourth Edition

Name

Function.call( ) — invoke a function as a method of an object

Availability

JavaScript 1.5; JScript 5.5; ECMAScript v3

Synopsis

                  function.call(thisobj, args...)

Arguments

thisobj

The object on which function is to be invoked. In the body of the function, thisobj becomes the value of the this keyword.

args...

Any number of arguments, which will 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.

Description

call( ) invokes the specified function as if it were a method of thisobj, passing it any arguments that follow thisobj in the argument list. The return value of call( ) is the value returned by the function invocation. Within the body of the function, the this keyword refers to the thisobj object.

Use Function.apply( ) instead if you want to specify the arguments to pass to the function in an array.

Example

// Call the default Object.toString(  ) method on an object that
// overrides it with its own version of the method. Note no arguments.
Object.prototype.toString.call(o);

See Also

Function.apply( )