Using Function object properties in ActionScript 1

Note: If you have never used ActionScript to write object-oriented scripts and don't need to target Flash Player 5, you should not use the information in this section, because writing scripts using ActionScript 1 is deprecated; instead, see Creating Classes with ActionScript 2.0 for information on using ActionScript 2.0.

You can specify the object that a function is applied to and the parameter values that are passed to the function, using the call() and apply() methods of the Function object. Every function in ActionScript is represented by a Function object, so all functions support call() and apply(). When you create a custom class using a constructor function, or when you define methods for a custom class using a function, you can invoke call() and apply() for the function.

Invoking a function using the Function.call() method in ActionScript 1

Note: If you have never used ActionScript to write object-oriented scripts and don't need to target Flash Player 5, you should not use the information in this section, because writing scripts using ActionScript 1 is deprecated; instead, see Creating Classes with ActionScript 2.0 for information on using ActionScript 2.0.

The Function.call() method invokes the function represented by a Function object.

In almost all cases, the function call operator (()) can be used instead of the call() method. The function call operator creates code that is concise and readable. The call() method is primarily useful when the this parameter of the function invocation needs to be explicitly controlled. Normally, if a function is invoked as a method of an object, within the body of the function, this is set to myObject, as in the following:

myObject.myMethod(1, 2, 3);

In some situations, you may want this to point somewhere else, for example, if a function must be invoked as a method of an object but is not actually stored as a method of that object.

myObject.myMethod.call(myOtherObject, 1, 2, 3); 

You can pass the value null for the thisObject parameter to invoke a function as a regular function and not as a method of an object. For example, the following function invocations are equivalent:

Math.sin(Math.PI / 4)
Math.sin.call(null, Math.PI / 4)

For more information, see Function.call().

To invoke a function using the Function.call method:

Specifying the object to which a function is applied using Function.apply() in ActionScript 1

Note: If you have never used ActionScript to write object-oriented scripts and don't need to target Flash Player 5, you should not use the information in this section, because writing scripts using ActionScript 1 is deprecated; instead, see Creating Classes with ActionScript 2.0 for information on using ActionScript 2.0.

The Function.apply() method specifies the value of this to be used within any function that ActionScript calls. This method also specifies the parameters to be passed to any called function.

The parameters are specified as an Array object. This is often useful when the number of parameters to be passed is not known until the script actually executes.

For more information, see Function.apply().

To specify the object to which a function is applied using Function.apply():