JavaScript® Bible, Sixth Edition

Chapter 34. Functions and Custom Objects

IN THIS CHAPTER

• Creating function blocks

• Passing parameters to functions

• Creating your own objects

By now, you've seen dozens of JavaScript functions in action and probably have a pretty good feel for the way they work. This chapter provides the function object specification and delves into the fun prospect of creating objects in your JavaScript code. If you've missed out on the object-oriented programming (OOP) revolution, then now is your chance to join. JavaScript is surprisingly full-featured when it comes to supporting OOP and allowing you to develop scripts that rely heavily on custom objects.

Function Object

Properties	Methods	Event Handlers
arguments	apply()
arity	call()
caller	toString()
constructor	valueOf()
length
prototype

Syntax

Creating a function object:

function functionName([arg1,...[,argN]]) {
   statement(s)
}

var funcName = new Function(["argName1",...[,"argNameN"],

   "statement1;...[;statementN]"])
object.eventHandlerName = function([arg1,...[,argN]]) {statement(s)}

Accessing function object properties and methods:

functionObject.property | method([parameters])

Compatibility: WinIE3+, MacIE3+, NN2+, Moz+, Safari+

About this object

JavaScript accommodates what other languages might call procedures, subroutines, and functions all in one type of structure: the custom function. A function may return a value (if programmed to do so with the return keyword), but it does not have to return any value. With the exception of JavaScript code that executes ...