Chapter 13. Windows and Frames
Chapter 12 described the Window object and the central role it
plays in client-side JavaScript. We've seen that the Window
object serves as the global object for client-side JavaScript
programs, and, as illustrated in Figure 12-1, it is
also the root of the client-side object hierarchy.
Besides these special roles, the Window object is an important object
in its own right. Every web browser window and every frame within
every window is represented by a Window object. The Window object
defines quite a few properties and methods that are important in
client-side JavaScript programming. This chapter explores those
properties and methods and demonstrates some important techniques for
programming with windows and frames. Note that because the Window
object is so central to client-side programming, this chapter is
quite long. Don't feel you have to master all this material at
once -- you may find it easier to study this chapter in several
shorter chunks!
13.1. Window Overview
We begin this chapter with an overview of some of the most commonly
used properties and methods of the Window object. Later sections of
the chapter explain this material in more detail. As usual, the
client-side reference section contains complete coverage of Window
object properties and methods.
The most important properties of the
Window object are the following:
- closed
-
A boolean
value that is true only if the window has been
closed.
- defaultStatus, status
-
The text that appears in the status
line of the browser.
- document
-
A reference to the Document object that
represents the HTML document displayed in the window. The Document
object is covered in detail in Chapter 14.
- frames[]
-
An array
of Window objects that represent the frames (if any) within the
window.
- history
-
A reference to the History object that represents the user's
browsing history for the window.
- location
-
A reference to the Location object that represents the URL of the
document displayed in the window. Setting this property causes the
browser to load a new document.
- name
-
The name of the window. Can be used
with the target attribute of the HTML
<a> tag, for example.
- opener
-
A
reference to the Window object that opened this one, or
null if this window was opened by the user.
- parent
-
If the current window is a frame, a
reference to the frame of the window that contains it.
- self
-
A self-referential property; a
reference to the current Window object. A synonym for
window.
- top
-
If the current window is a
frame, a reference to
the Window object of the top-level window that contains the frame.
Note that top is different from
parent for frames nested within other frames.
- window
-
A self-referential property; a
reference to the current Window object. A synonym for
self.
The Window
object also supports a number of important methods:
- alert( )
, confirm( ), prompt( )
-
Display simple dialog boxes to the user and, for
confirm( ) and prompt( ), get
the user's response.
- close( )
-
Close the window.
- focus( )
, blur( )
-
Request or relinquish keyboard focus for the window. The
focus( ) method also ensures that the window is
visible by bringing it to the front of the stacking order.
- moveBy( )
, moveTo( )
-
Move the window.
- open( )
-
Open a new top-level window to display a specified
URL with a specified set of features.
- print( )
-
Print the window or frame -- same as if the user had selected the
Print button from the window's
toolbar (Netscape 4 and later and IE 5 and later only).
- resizeBy( )
, resizeTo( )
-
Resize the window.
- scrollBy( )
, scrollTo( )
-
Scroll the document displayed within the window.
- setInterval( )
, clearInterval( )
-
Schedule or cancel a function to be repeatedly invoked with a
specified delay between invocations.
- setTimeout( )
, clearTimeout( )
-
Schedule or cancel a
function to be
invoked once after a specified number of milliseconds.
As you can see from these lists, the Window object provides quite a
bit of functionality. The remainder of this chapter explores much of
that functionality in more detail.
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| 12.3. Execution of JavaScript Programs |  | 13.2. Simple Dialog Boxes |
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