6.2 Objects and methods

Objects are a natural way of thinking about the world and of writing scripts that manipulate XHTML documents.  Java Script uses objects to perform many tasks and therefore referred to as and ovject-based programming language.

It facilitates objects to be defined ad used in the documents.  All objects in the real world have attributes such as size, shape color, weight and the like; and they all exhibit behaviours, for example a ball rolls, bounces, inflates and deflates, a baby cries, sleeps, crawls and walks.  Humans learn about  objects by studying their attributes and observing their behaviors.  Objects encapsulate data(properties) and methods.  A java script object is a composition of its properties and method.  For example a student has name, number, mark1, mark2, as its properties and total calculation and average are methods.

Java script handles the HTML documents and the related objects such as windows, forms and screen in a specific hierarchy.  This hierarchy is called the Document Object Model (DOM) which is directly related to the browsers.  The properties of the object covered in the DOM get their values supplied by the browser.

The following table shows the most commonly used Java Script objects.

Table 6.1. Hierarchy of Objects their Properties and Methods.

Objects properties Methods
Window Default Status Alert
Frames Blur
Opener Close
Parent Confirm
Scroll Open
Self Focus
Status Prompt
Top ClearTimeout
Window Set Timeout
Frame Defaultstatus Alert
Frames Blur
Opener Close
Parent Confirm
Scroll Open
Self Focus
Status Prompt
Top clearTimeout
Window setTimeout
Location Hash Reload
Host Replace
Hostname
Href
Pathname
Protocol
Search
History Length Black
Forward
go
Navigator AppCodename JavaEnabled
AppName
AppVersion
mimerType
Plugin
userAgent
Document alinkColor Clear
Area Close
Anchors Open
Applets Write
Bgcolour writeIn
Cookie
Fgcolor
Cookie
Fgcolor
Forms
Images
lastModified
linkColor
Links
location
Referrer
Title
vlinkColor
Image Border None
Complete
Height
Hspace
Lowsrc
Src
Vspace
Width
Form action onSubmit
Elements OnReset
Encoding
FileUpload
Method
Name
Target
Text Defaultvalue OnBlur
Name OnFocus
Type OnChange
value OnSelect

 

JavaScript also supports built in objects such as Array, Date and string.

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One Response to “6.2 Objects and methods”

  1. silver price says:

    In JavaScript you can define your own objects. In addition, you can assign methods and properties to each object, pre-written or self-defined.

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