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object always

</head>

</frameset>

</html>

This code creates a frameset with one frame across the top and two frames underneath. Here, the top

frame can be referenced by

window.frames[0]

window.frames[“topFrame”]

, however, you would

probably use the

top

object instead of

window

to refer to these frames (making it

top.frames[0]

, for

instance).

The

top

object always points to the very top (outermost) frame, which is the browser window itself. This

assures that you are pointing to the correct frame. If you then write code within a frame, the

window

object referenced in it is a pointer to just that frame.

Because the window object is the center of the BOM universe, it enjoys a special privilege: You don’t

need to explicitly reference it. Whenever a function, object, or collection is referenced, the interpreter

always looks to the

window

object, so

window.frames[0]

can be rewritten as just

frames[0]

. To

understand the various ways to reference the frames in the previous example, refer to Figure 5-4.

Figure 5-4

It is also possible to access a frame directly using its name, such as

window.leftFrame

. However,

using the

frames

collection is generally more acceptable because it more accurately represents the

code’s intent.

Another instance of the window object is called

parent

. The

parent

object is used with framesets that

load files that are also framesets. Suppose the file named

frameset1.htm

contains this code:

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JavaScript in the Browser

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