HTML and CSS Reference
In-Depth Information
the
window
, because JavaScript knows that the window is at the top of the tree. Instead of
saying
window.document.bgcolor
, you can simply say
document.bgcolor
.
The
document
object is a property of the
window
object, and if the window is partitioned
into frames (subwindows), each frame is a property of the
window
object.
Every window (or frame) contains a
document
object that corresponds to the HTML
document shown in the window. This object corresponds mainly to the body of the doc-
ument—that is, what is inserted between the
<body></body>
tags. JavaScript programs
manipulate this object to bring life to otherwise dead, static pages. Because the
document
object is below the
window
object, the
document
object can be represented as a property
of the
window
by saying
window.document
. The
forms
object is an array of objects below
the
document
object, so the
forms
object is a property of the
document
object and is rep-
resented as
window.document.forms[]
.
As stated before, because the
window
object is at the top of the hierarchy, any objects
just below it, such as the
document
or
location
objects, are
window
properties and the
word
window
is not required; thus, specifying
window.document.bgColor
is the same as
document.bgcolor.
The syntax for describing the background color (
bgcolor
) property for a document
object is shown in the following example:
document.bgcolor = "yellow";
Document Properties.
The
document
object is defined when the HTML
<body>
tag is
encountered on the page and stays in existence until the page exits. The
<body>
tag has a
number of attributes that define the appearance of the page. The
document
object has prop-
erties that correspond to the HTML
<body>
tag attributes, as shown in Tables 11.1 and
11.2. The properties of the
document
object are shown in the output of Example 11.2. (See
Chapter 13, “Handling Events,” for events that are associated with the
<body>
tag.)
Table 11.1
HTML
<body>
Tag Attributes
Attribute
What It Specifies
alink
Color of an active link; that is, while the mouse is on the link.
background
URL of a background image.
bgcolor
Background color of the page.
fgcolor
Text or foreground color.
link
Color of an unvisited link.
vlink
Color of a visited link.
