Properties of the window Object

As we know, the window object is the big cheese of browser objects, corresponding to the browser window and containing, among other objects, the document , location , and history objects. Those objects are available through properties of the same name in the window object; for example, we've already seen how to navigate the browser to a URL the user types using the loca tion objectwhich is part of the window objectlike this (this is Listing 04-06.html on the web sitemore on the location object in Chapter 10, "Using the navigator , location , and history Objects"):

 <HTML>      <HEAD>          <TITLE>              Navigate to an URL          </TITLE>          <SCRIPT LANGUAGE = "JavaScript">              <!--             function Jump()              {  window.location.href = document.form1.text1.value  }              // -->          </SCRIPT>      </HEAD>      <BODY>          <H1>Navigate to an URL</H1>          <FORM NAME = "form1">              <BR>              <INPUT TYPE = TEXT NAME="text1" SIZE = 80>              <BR>              <BR>              <INPUT TYPE = BUTTON Value="Navigate to URL" ONCLICK="Jump()">          </FORM>      </BODY>  </HTML>

Tip

Because the window object is the overall containing object in a browser, you can usually omit referring to it when using its properties, events, and methods if there's no possibility of confusion. For example, I could have written window.location.href = document.form1.text1.value above as location.href = document.form1.text1.value .

You can find an overview of the properties of the window object in Table 7.1 (note that not all properties apply to all browsers), and property-by-property coverage in Table 7.2. In this chapter, we'll discuss those properties.

Table 7.1. Overview of the Properties of the window Object

Properties
`appCore`	`clientInformation`	`clipboardData`	`closed`
`Components`	`controllers`	`crypto`	`defaultStatus`
`dialogArguments`	`dialogHeight`	`dialogLeft`	`dialogTop`
`dialogWidth`	`directories`	`document`	`event`
`external`	`frameElement`	`frames`	`history`
`innerHeight`	`innerWidth`	`length`	`loading`
`location`	`locationbar`	`menubar`	`name`
`navigator`	`offscreenBuffering`	`opener`	`outerHeight`
`outerWidth`	`pageXOffset`	`pageYOffset`	`parent`
`personalbar`	`pkcs11`	`prompter`	`returnValue`
`screen`	`screenLeft`	`screenTop`	`screenX`
`screenY`	`scrollbars`	`scrollX`	`scrollY`
`self`	`sidebar`	`status`	`statusbar`
`toolbar`	`top`	`window`

Table 7.2. The Properties of the window Object

Property	NS2	NS3	NS4	NS6	IE3a	IE3b	IE4	IE5	IE5.5	IE6
`appCore`				x
	Read-only
	This property is a Netscape 6.0 property that allows scripting access (called XPConnect) to COM objects and Netscape's XML-based XUL objects. See www.mozilla.org/scriptable/ for the details.
`clientInformation`							x	x	x	x
	Read-only
	Another name for the `navigator` object in the Internet Explorer.
`clipboardData`								x	x	x
	Read/write
	Allows access to the clipboard. See "Using the Clipboard" in this chapter for the details, as well as "The oncopy Event" in Chapter 6, "Using Core HTML Methods and Events."
`closed`		x	x	x				x	x	x
	Read-only
	Set to true if a `window` object has been closed, and false otherwise . Useful if you're handling multiple `window` objects at the same time. See "Working with New Windows " in this chapter for an example.
`Components`				x
	Read-only
	This property is a Netscape 6.0 property that allows scripting access (Called XPConnect) to COM objects and Netscape's XML-based XUL objects. See www.mozilla.org/scriptable/ for the details.
`controllers`				x
	Read-only
	This property is a Netscape 6.0 property that allows scripting access (Called XPConnect) to COM objects and Netscape's XML-based XUL objects. See www.mozilla.org/scriptable/ for the details.
`crypto`				x
	Read-only
	This property is used in Netscape's public-key cryptography efforts; for more details, see www.mozilla.org/projects/security.
`defaultStatus`	x	x	x	x	x	x	x	x	x	x
	Read/write
	Holds the default text for the status bar (visible when the page first loads). If the mouse moves over a link, the default text will be replaced temporarily and restored when the mouse leaves the link. See "Accessing the Status Bar" in this chapter for an example.
`dialogArguments`							x	x	x	x
	Read-only
	Holds arguments passed to dialog boxes (used to initialize the dialog boxes), which are windows opened with the Internet Explorer methods `showModalDialog` and `showModelessDialog` . See "Creating Dialog Boxes" in this chapter for an example. More on the `showModalDialog` and `showModelessDialog` methods in Chapter 8, "Using window and frame Methods and Events."
`dialogHeight`							x	x	x	x
	Read/write
	Sets or gets the height of dialog boxes, which are windows opened with the Internet Explorer methods `showModalDialog` and `showModelessDialog` . See "Creating Dialog Boxes" in this chapter for an example. More on the `showModalDialog` and `showModelessDialog` methods in Chapter 8.Values include `"px"` to indicate pixel measurements, like this: `"300px"` .
`dialogLeft`							x	x	x	x
	Read/write
	Sets the left position of dialog boxes, which are windows opened with the Internet Explorer methods `showModalDialog` and `showModelessDialog` . See "Creating Dialog Boxes" in this chapter for an example. More on the `showModalDialog` and `showModelessDialog` methods in Chapter 8.Values include `"px"` to indicate pixel measurements, like this: `"300px"` .
`dialogTop`							x	x	x	x
	Read/write
	Sets the top position of dialog boxes, which are windows opened with the Internet Explorer methods `showModalDialog` and `showModelessDialog` . See "Creating Dialog Boxes" in this chapter for an example. More on the `showModalDialog` and `showModelessDialog` methods in Chapter 8.Values include `"px"` to indicate pixel measurements, like this: `"300px"` .
`dialogWidth`							x	x	x	x
	Read/write
	Sets the width of dialog boxes, which are windows opened with the Internet Explorer methods `showModalDialog` and `showModelessDialog` . See "Creating Dialog Boxes" in this chapter for an example. More on the `showModalDialog` and `showModelessDialog` methods in Chapter 8. Values include `"px"` to indicate pixel measurements, like this: `"300px"` .
`directories`			x	x
	Read/write
	One of the properties that enables you to customize the appearance of the Netscape Navigator by displaying or hiding menu bars, location bars, and so on. See "Displaying and Hiding Netscape Navigator Bars" in this chapter.
`document`	x	x	x	x	x	x	x	x	x	x
	Read-only
	The `document` object. See Chapter 9, "Using the document and body Objects," for the details.
`event`							x	x	x	x
	Read/write
	The global `event` object in the Internet Explorer, holding data about events that have occurred. See Chapter 6 for the details.
`external`							x	x	x	x
	Read-only
	This property gives you access to a host application when the Internet Explorer is being run from such an application. This property corresponds to the `external` object, which includes methods such as `AddDesktopComponent(URL, Type [, Left] [, Top] [, Width]` `[, Height])` to add a desktop component (set `Type` to `"website"` or
	`"image"` , and `AddFavorite(URL [, Title])` , which adds an URL to the Internet Explorer's favorites list; here's an example showing how to use `AddFavorite:` `window.external.AddFavorite(location.href,` `document.title)` .
`frameElement`									x	x
	Read-only
	If a window is being displayed in a frame, this property returns the parent `<FRAME>` or `<IFRAME>` element.
`frames`	x	x	x	x	x	x	x	x	x	x
	Read-only
	Holds an array of frames contained by a window. See "Using Frame Properties" in this chapter for an example.
`history`	x	x	x	x	x	x	x	x	x	x
	Read-only
	The `history` object, which holds the browser's past locations. See Chapter 10 for the details.
`innerHeight`			x	x
	Read/write
	Holds the height of the client area of the browser (where the document is displayed). The Netscape Navigator enables you to change this property on-the-fly . See "Setting the Netscape Navigator's Dimensions" in this chapter for an example.
`innerWidth`			x	x
	Read/write
	Holds the width of the client area of the browser (where the document is displayed). The Netscape Navigator enables you to change this property on-the-fly. See "Setting the Netscape Navigator's Dimensions" in this chapter for an example.
`length`	A JavaScript HTML core property. See Chapter 5, "Using Core HTML Properties."
`loading`			x
	Read-only
	Returns true if a window is still being loaded, and false otherwise. Specific to Netscape Navigator 4.0 only!
`location`	x	x	x	x	x	x	x	x	x	x
	Read/write
	The `location` object. See Chapter 10 for the details.
`locationbar`			x	x
	Read/write
	One of the properties that enables you to customize the appearance of the Netscape Navigator by displaying or hiding menu bars, location bars, and so on. See "Displaying and Hiding Netscape Navigator Bars" in this chapter for an example.
`menubar`			x	x
	Read/write
	One of the properties that enables you to customize the appearance of the Netscape Navigator by displaying or hiding menu bars, location bars, and so on. See "Displaying and Hiding Netscape Navigator Bars" in this chapter for an example.
`name`	x	x	x	x	x	x	x	x	x	x
	Read/write
	A window's name. By default, a top-level window has no name, although you can supply one with the `window.name` property. Windows are often given names in `<FRAMESET>` elements; see "Using Frame Properties" in this chapter for an example.
`navigator`				x			x	x	x	x
	Read-only
	The `navigator` object. See Chapter 10.
`offscreenBuffering`							x	x	x	x
	Read/write
	Specifies whether the Internet Explorer draws a page in memory before displaying it on the screen. A page saved in memory can be presented immediately to the user (that is, the user won't have to watch the page being constructed piece-by-piece on the screen). The default value here is `auto` , which lets the Internet Explorer decide when to use offscreen buffering. You can turn on offscreen buffering by setting this value to true, or turn it off by setting it to false.
`opener`		x	x	x	x	x	x	x	x	x
	Read-only
	The window that opened the current window. This property gives you access to a parent window; see "Working with New Windows" in this chapter for an example.
`outerHeight`			x	x
	Read/write
	Holds the height of the browser itself. The Netscape Navigator enables you to change this property on-the-fly. See "Setting the Netscape Navigator's Dimensions" in this chapter for an example.
`outerWidth`			x	x
	Read/write
	Holds the width of the browser itself. The Netscape Navigator enables you to change this property on-the-fly. See "Setting the Netscape Navigator's Dimensions" in this chapter for an example.
`pageXOffset`			x	x
	Read-only
	The X coordinate (in document coordinates) of the top left of the client area (the area where the document is displayed) when the document has been scrolled.
`pageYOffset`			x	x
	Read-only
	The Y coordinate (in document coordinates) of the top left of the client area (the area where the document is displayed) when the document has been scrolled.
`parent`	x	x	x	x	x	x	x	x	x	x
	Read-only
	Usually used when you're working with windows in frames. This property corresponds to the window's parent `window` object. See "Using Frame Properties" in this chapter for an example.
`personalbar`			x	x
	Read/write
	One of the properties that enables you to customize the appearance of the Netscape Navigator by displaying or hiding menu bars, location bars, and so on. See "Displaying and Hiding Netscape Navigator Bars" in this chapter for an example.
`pkcs11`				x
	Read-only
	This property is used in Netscape's public-key cryptography efforts; for more details, see www.mozilla.org/projects/security.
`prompter`				x
	Read-only
	This property is a Netscape 6.0 property that allows scripting access (called XPConnect) to COM objects and Netscape's XML-based XUL objects. See www.mozilla.org/scriptable/ for the details.
`returnValue`							x	x	x	x
	Read/write
	Holds the return value from dialog boxes, which are windows opened with the Internet Explorer methods `showModalDialog` and `showModelessDialog` . This return value can be an array of values set by the user in the dialog box. See "Creating Dialog Boxes" in this chapter for an example.
`screen`				x			x	x	x	x
	Read-only
	The `screen` object, which holds data about the screen, such as its dimensions. See "The `screen` Object" in this chapter for an example.
`screenLeft`								x	x	x
	Read-only
	Holds the left position of the client area (the area where the document is displayed, excluding toolbars , menu bars, and so on) with respect to the top left of the screen (which is treated as (0, 0)). Measured in pixels.
`screenTop`								x	x	x
	Read-only
	Holds the top of the client area (the area where the document is displayed, excluding toolbars, menu bars, and so on) with respect to the upper-left corner of the screen (which is treated as (0, 0)). Measured in pixels.
`screenX`				x
	Read/write
	Holds the X position of the left edge of the browser in screen coordinates (where the upper left corner of the screen is (0, 0)). Measured in pixels.
`screenY`				x
	Read/write
	Holds the Y position of the top edge of the browser in screen coordinates (where the upper-left corner of the screen is (0, 0)). Measured in pixels.
`scrollbars`			x	x
	Read/write
	One of the properties that enables you to customize the appearance of the Netscape Navigator by displaying or hiding menu bars, location bars, and so on. See "Displaying and Hiding Netscape Navigator Bars" in this chapter for an example.
`scrollX`				x
	Read-only
	Holds the horizontal position of a scrolled window. Measured in pixels.
`scrollY`				x
	Read-only
	Holds the vertical position of a scrolled window. Measured in pixels.
`self`	x	x	x	x	x	x	x	x	x	x
	Read-only
	Refers to the current window (just like using the `window` object for the current window).
`sidebar`				x
	Read-only
	This property is a Netscape 6.0 property that allows scripting access (called XPConnect) to COM objects and Netscape's XML-based XUL objects. See www.mozilla.org/scriptable/ for the details.
`status`	x	x	x	x	x	x	x	x	x	x
	Read/write
	Holds the text displayed in the browser's status bar. See "Accessing the Status Bar" in this chapter for an example.
`statusbar`			x	x
	Read/write
	One of the properties that enables you to customize the appearance of the Netscape Navigator by displaying or hiding menu bars, location bars, and so on. See "Displaying and Hiding Netscape Navigator Bars" in this chapter for an example.
`toolbar`			x	x
	Read/write
	One of the properties that enables you to customize the appearance of the Netscape Navigator by displaying or hiding menu bars, location bars, and so on. See "Displaying and Hiding Netscape Navigator Bars" in this chapter for an example.
`top`	x	x	x	x	x	x	x	x	x	x
	Read-only
	Refers to the top window in a window hierarchy. When you are using frames, for example, top refers to the topmost containing window. See "Using Frame Properties" in this chapter for an example.
`window`	x	x	x	x	x	x	x	x	x	x
	Read-only
	The same as the `window` object itself, even though this is a property of the `window` object. (There's no real reason to use this property.)

As you can see in Table 7.2, the window object has a great many properties. Let's put them to work.