Function.apply()

Availability

Flash Player 6.

Usage

myFunction.apply(thisObject, argumentsObject)

Parameters

thisObject The object that myFunction is applied to.

argumentsObject An array whose elements are passed to myFunction as parameters.

Returns

Any value that the called function specifies.

Description

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. Because apply() is a method of the Function class, it is also a method of every function object in ActionScript.

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.

Example

The following function invocations are equivalent:

Math.atan2(1, 0)
Math.atan2.apply(null, [1, 0])

You could construct a SWF file that contains input entry fields that permit the user to enter the name of a function to invoke, and zero or more parameters to pass to the function. Pressing a "Call" button would then use the apply method to call the function, specifying the parameters.

In this example, the user specifies a function name in an input text field called functionName. The number of parameters is specified in an input text field called numParameters. Up to 10 parameters are specified in text fields called parameter1, parameter2, up to parameter10.

on (release) {
  callTheFunction();
}
...
function callTheFunction()
{
   var theFunction = eval(functionName.text);
   var n = Number(numParameters);
   var parameters = [];
   for (var i = 0; i < n; i++) {
      parameters.push(eval("parameter" + i));
   }
   theFunction.apply(null, parameters);
}