Functions are very useful part of ActionScript3 as they save the time, reduce the code and also increases the re-usability of the code. Function is that block or piece of code which can be used reused at any point in the code. They save the time as they can be called any number of times when required.

Calling the Functions
The calling of the function is done by using the parentheses operator.For Example the use of TRACE( ) function is shown below:

trace( " USED FOR DEBUGGING THE SCRIPT ");

Incase you are calling a function with no parameters in it then in that case empty pair of parentheses should be used.For Example

var random:Number = Math.random();

Defining Your Own Function

In ActionScript3 there are two ways of defining the functions.

1. Function Statement
2. Function Expression

1. FUNCTION STATEMENT :The function statements are used if you want to define your functions static or stricted. A function statement starts with the function keyword. The following is the syntax for the function statement :-

function traceParameter(aParam:String) 
{ 
    trace(aParam); 
} 

traceParameter("hello"); // hello

2. FUNCTION EXPRESSION: The function expressions are used to when you have to define more dynamic or standard programming. Function expression were used in the earlier versions of the ActionScript. The Syntax for this is as follows:-

var traceParameter:Function = function (aParam:String) 
{ 
    trace(aParam); 
}; 
traceParameter("hello"); // hello