JavaScript Bible, Gold Edition part 47 ppsx

cols rows NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5 The colsand rowsproperties of a FRAMESET element object let you read and modify the sizes of frames after the frameset has loaded..

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Example on the CD-ROM

Related Items:FRAME.borderColor, FRAMESET.frameBorderproperties

cols

rows

NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5

The colsand rowsproperties of a FRAMESET element object let you read and modify the sizes of frames after the frameset has loaded These two properties are defined in the W3C DOM Values for both properties are strings, which may include percent symbols or asterisks Therefore if you are trying to increase or decrease the size of a frame column or row gradually, you must parse the string for the nec-essary original values before performing any math on them (or, in IE4+, use the FRAME element object’s heightand widthproperties to gauge the current frame size in pixels)

IE4+ lets you completely modify the frameset by adjusting these properties This includes adding or removing columns or rows to the frameset grid Because a change in the frameset structure could impact scripts by changing the size of the frames array associated with the parent window or unloading documents that con-tain needed data, be sure to test your scripts with both states of your frameset If you want to remove a frame from a frameset view, you might be safer to specify the size of zero for that particular row or column in the frameset Of course a size of zero still leaves a one-pixel frame, but it is essentially invisible if borders are not turned on and the one-pixel frame shares the same background color as the other frames Another positive by-product of this technique is that you can restore the other frame with its document state identical from when it was hidden

When you have nested framesets defined in a single document, be sure to refer-ence the desired FRAMESET element object One object may be specifying the columns, while another (nested) one specifies the rows for the grid Assign a unique ID to each FRAMESET element so that references can be reliably directed to the proper object

Example (with Listings 16-46, 16-47, and 16-48) on the CD-ROM

Related Items: FRAME object.

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FRAMESET.cols

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Value:yes| no| 1| 0as strings Read/Write

The frameBorderproperty offers scripted access to a FRAMESET element

object’s FRAMEBORDER attribute setting IE4+ does not respond well to modifying

this property after the page has loaded

Values for the frameBorderproperty are strings that substitute for Boolean

values Values yesor 1mean that the border is (supposed to be) turned on; noor 0

turn off the border

Related Items:FRAME.frameBorderproperties

frameSpacing

The frameSpacingproperty of a FRAMESET element object lets you read the

spacing (in pixels) between frames of a frameset If you do not specify a

FRAMES-PACING attribute in the frameset’s tag, the property is empty, rather than reflecting

the actual border thickness applied by default (usually 2)

Related Items:FRAMESET.borderproperty

On the

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On the

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FRAMESET.frameSpacing

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IFRAME Element Object

For HTML element properties, methods, and event handlers, see Chapter 15

align contentDocument Document

frameBorder frameSpacing hspace longDesc marginHeight marginWidth scrolling src vspace

Syntax

Accessing properties or methods of an IFRAME element object from a containing document:

(IE4+) document.all.iframeID property | method([parameters]) (IE4+/NN6) window.frames[“iframeName”] property | method([parameters]) (IE5+/NN6) document.getElementById(“iframeID”) property | method([parameters])

Accessing properties of methods of an IFRAME element from a document inside the IFRAME element:

(IE4+) parent.document.all.iframeID property | method([parameters]) (IE5+/NN6) parent.document.getElementById(“iframeID”) property |

method([parameters])

About this object

An IFRAME element (IE4+ and NN6) allows HTML content from a separate source

to be loaded within the body of another document In some respects, the NN4 LAYER element was a precursor to the IFRAME concept, but unlike the LAYER, an IFRAME element is not inherently positionable It is positionable, the same way as any other HTML element, by assigning positioning attributes to a style sheet associ-ated with the IFRAME Without explicit positioning, an IFRAME element appears in

IFRAME

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the body of a document in normal source code order of elements Unlike a frame of

a frameset, you can place an IFRAME arbitrarily in the middle of any document If

the FRAME changes size under script control, the surrounding content moves out

of the way or cinches up

What truly separates the IFRAME apart from other HTML elements is its ability

to load and display external HTML files and, with the help of scripts, have different

pages loaded into the IFRAME without disturbing the rest of the content of the main

document Pages loaded into the IFRAME can also have scripts and any other

fea-tures that you may like to put into an HTML document (including XML)

The IFRAME element has a rich set of attributes that let the HTML author control

the look, size (HEIGHTand WIDTH), and, to some degree, behavior of the frame

Most of those are accessible to scripts as properties of an IFRAME element object

It is important to bear in mind that an IFRAME element is in many respects like a

FRAME element, especially when it comes to window kinds of relationships If you

plant an IFRAME element in a document of the main window, that element shows up

in the main window’s object model as a frame, accessible via common frames

termi-nology:

window.frames[i]

window.frames[frameName]

Within that IFRAME frame object is a document and all its contents All

refer-ences to the document objects inside the IFRAME must flow through the “portal” of

the IFRAME frame

Conversely, scripts in the document living inside an IFRAME can communicate

with the main document via the parentreference Of course, you cannot replace

the content of the main window with another HTML document (using

location.href, for instance) without destroying the IFRAME that was in the

origi-nal document

Properties

align

The alignproperty governs how an IFRAME element aligns itself with respect to

surrounding content on the page Two of the possible values (leftand right)

position the IFRAMEalong the left and right edge (respectively) of the IFRAME’s

containing element (usually the BODY) Just as with an image, when an IFRAME is

floated along the left and right edges of a container, other content wraps around the

element Table 16-5 shows all possible values and their meanings

IFRAME.align

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Table 16-5 Values of the align Property

Value Description

absbottom Aligns the bottom of the IFRAME with the imaginary line that

extends along character descenders of surrounding text.

absmiddle Aligns the middle of the IFRAME with the center point between

the surrounding text’s top and absbottom.

baseline Aligns the bottom of the IFRAME with the baseline of

surrounding text.

bottom Same as baseline in IE.

left Aligns the IFRAME flush with left edge of the containing element middle Aligns the imaginary vertical centerline of surrounding text with

the same for the IFRAME element.

right Aligns the IFRAME flush with the right edge of the containing

element.

texttop Aligns the top of the IFRAME element with the imaginary line

that extends along the tallest ascender of surrounding text top Aligns the top of the IFRAME element with the surrounding

element’s top.

As your script changes the value of the alignproperty, the page automatically reflows the content to suit the new alignment

Related Items:IFRAME.hspace, IFRAME.vspaceproperties

contentDocument

The contentDocumentproperty of an IFRAME element object is nothing more than a reference to the document contained by that frame If your script finds that

it has a reference to an IFRAME element object, you can use the contentDocument property to get a valid reference to the document, and therefore any other content

of the frame

On the

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IFRAME.contentDocument

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Related Items:documentobject

Document

See the FRAME.Documentproperty for details on this property of the ActiveX

Web Browser object You find less need for this property with an IFRAME element,

because you can use the windowobject behavior of IFRAMEs to transcend the

doc-ument object hierarchies of the main window and the IFRAME window

Related Items:FRAME.Documentproperty

frameBorder

The frameBorderproperty offers scripted access to an IFRAME element object’s

FRAMEBORDERattribute setting IE4+ does not respond well to modifying this

prop-erty after the page has loaded

Values for the frameBorderproperty are strings that substitute for Boolean

val-ues Values yesor 1mean that the border is (supposed to be) turned on; noor 0

turn off the border

Related Items:FRAME.frameBorderproperties

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IFRAME.frameBorder

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The frameSpacingproperty is included in IE5 for backward compatibility to IE4’s erroneous inclusion of this property for an IFRAME element Do not use it

hspace

vspace

Value: Integer Read/Write

These IE-specific properties allow for margins to be set around an IFRAME ele-ment In general, hspaceand vspaceproperties (and their HTML attributes) have been replaced by CSS margins and padding These properties and their attributes are not recognized by any W3C standard (including HTML 4.0)

Values for these properties are integers representing the number of pixels of padding between the element and surrounding content The hspacevalue assigns the same number of pixels to the left and right sides of the element; the vspace value is applied to both the top and bottom edges Scripted changes to these values have no effect in IE5/Windows

Related Items:style.paddingproperty

longDesc

Value: URL String Read/Write

The longDescproperty is the scripted equivalent of the LONGDESCattribute of the <IFRAME>tag This HTML 4.0 attribute is intended to provide browsers with a URL to a document that contains a long description of the element Future browsers

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IFRAME.longDesc

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can use this feature to provide information about the frame for visually impaired

site visitors

marginHeight

marginWidth

Browsers tend to automatically insert content within a frame by adding a margin

between the content and the edge of the frame These values are represented by

the marginHeight(top and bottom edges) and marginWidth(left and right edges)

properties Although the properties are not read-only, changing the values after the

frameset has loaded does not alter the appearance of the document in the frame If

you need to alter the margin(s) of a document inside a frame, adjust the

docu-ment.body.stylemargin properties

Also be aware that although the default values of these properties are empty

(that is, when no MARGINHEIGHTor MARGINWIDTHattributes are set for the

<IFRAME>tag), margins are built into the page The precise pixel count of those

margins varies with different operating systems

Related Items:styleobject (Chapter 30)

scrolling

The scrollingproperty lets scripts turn scrollbars on and off inside an IFRAME

element By default, scrolling is turned on unless overridden by the SCROLL

attribute of the <IFRAME>tag

Values for the scrollingproperty are strings that substitute for Boolean values

Values yesor 1mean that scrollbars are visible (provided there is more content

than can be viewed without scrolling); noor 0hide scrollbars in the frame IE4+

also recognizes (and sets as default) the auto value

Related Items:FRAME.scrollingproperty

On the

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IFRAME.scrolling

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The srcproperty of an IFRAME element object offers an additional way of navi-gating to a different page within an inline frame (that is, other than assigning a new URL to the location.hrefproperty of the frame object) Remember that the src property belongs to the IFRAME element object, not the windowobject it repre-sents Therefore, references to the srcproperty must be via the element’s ID and/or node hierarchy

Related Items:location.hrefproperty

popup Object

Properties Methods Event Handlers

Syntax

Creating a popupobject:

var popupObj = window.createPopup()

Accessing properties or methods of a popupobject from a document in the win-dow that created the pop-up:

popupObj.property | method([parameters])

On the

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popup

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About this object

A popupobject is a chrome-less window space, which overlaps the window

whose document generates the pop-up A pop-up also appears in front of any dialog

boxes Unlike the dialog box windows generated via IE’s showModalDialog()and

showModelessDialog()methods, your scripts must not only create the window,

but also put content into it, and then define where on the screen and how big it will

be

Because the pop-up window has no chrome (that is, title bar, resize handles, and

so forth), you should populate its content with a border and/or background color

so that it stands out from the main window’s content The following statements

reflect a typical sequence of creating, populating, and showing a popupobject:

var popup = window.createPopup()

var popupBody = popup.document.body

popupBody.style.border = “solid 2px black”

popupBody.style.padding = “5px”

popupBody.innerHTML = “<P>Here is some text in a popup window</P>”

popup.show(200,100, 200, 50, document.body)

The pop-up window that IE creates is, in fact, a window, but only from the point

of view of the document that it contains In other words, while the number of

prop-erties and methods for the popupobject is small, the parentWindowproperty of

the document inside the pop-up points to a genuine windowproperty Even so, be

aware that this pop-up does not appear as a distinct window among windows listed

in the Windows Taskbar If a user clicks outside of the pop-up or switches to

another application, the pop-up disappears, and you must reinvoke the show()

method by script (complete with dimension and position parameters) to force the

pop-up to reappear

When you assign content to a pop-up, you are also responsible for making sure

that the content fits the size of the pop-up you specify If the content runs past the

rectangular space (body text word wraps within the pop-up’s rectangle), no

scroll-bars appear

Properties

document

Use the documentproperty as a gateway to the content of a pop-up window This

property is the only access point available from the script that creates the pop-up

to the pop-up itself The most common application of this property is to set

docu-ment properties governing the content of the pop-up window For example, to give

the pop-up a border (because the pop-up itself has no window chrome), the script

popupObject.document

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