HTML 4.01 in Netscape and Explorer: Proprietary Elements | WebReference

HTML 4.01 in Netscape and Explorer: Proprietary Elements

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HTML 4.01 in Netscape and ExplorerProprietary Elements

The following elements are not in the HTML 4.0 specification, but are supported by one or both of Netscape and Explorer. Some are older HTML elements that have been dropped for the newer specification, and others are proprietary extensions that Microsoft or Netscape have implemented. Their use is discouraged, since their effects can almost always be accomplished in other ways.

bgsound (Explorer)

Attributes

AttributeTypeDescription
srcURIURI of the sound to be played
loopNumberNumber of times the sound should be repeated
volumeSigned NumberVolume of sound to be played. Range is -10000 (lowest) to 0 (highest).
balanceSigned NumberLeft/right balance of sound. Range is -10000 to +10000. 0 represents centered sound.

Details

Contained in:head
Contains:Empty
Start tag:Required
End tag:Forbidden

The bgsound element is used to include a background sound for your document. It is only supported by Explorer and is generally not a good idea, since Explorer offers no way to stop the playing the sound short of turning down the volume on your speakers, so it can be very annoying.

marquee (Explorer)

Attributes

AttributeTypeDescription
behaviorCDATABehaviour of the marquee. May be alternate, scroll or slide.
directionCDATADirection in which the marquee should move. May be up, down, left or right.
loopnumberNumber of times marquee should loop.
scrollamountnumberNumber of pixels marquee should advance per step.
scrolldelaynumberNumber of milliseconds of delay between steps.
truespeedbooleanPrevents rounding of scrolldelay values of less than 60 to 60.
bgcolorcolorBackground color.
heightlengthHeight of Marquee. Percentages refer to screen height.
widthlengthWidth of Marquee.
hspacepixelsHorizontal space between marquee and surroundings.
vspacepixelsVertical space between marquee and surroundings.

Details

Contained in:%flow
Contains:%flow
Start tag:Required
End tag:Required

The contents of the marquee element are scrolled at the speed specified by the scrollamount and scrolldelay attrubutes (scrolldelay values of less than 60 are always considered 60 unless the truespeed attribute is present). The exact method of scrolling depends on the behavior attribute. behavior=alternate indicates that the marquee "bounces" from one end to the other and back again. behavior=scroll indicates that the marquee scrolls from one side and disappears into the other side. behavior=scroll indicates that the marquee should appear on one side, scroll to the other side, and then stop.

embed (Explorer) (Netscape)

Attributes

AttributeTypeDescription
srcURIURI of object to be displayed
codeURI(Explorer only) URI of an embedded applet
codebaseURI(Explorer only) Base URI for embedded applet
pluginspaceURI(Netscape only) URI for instructions for installing the plug-in required by the object
pluginurlURI(Netscape only) URI for a Java Archive (JAR) which contains an installable version of the plugin.
borderpixels(Netscape only) Border width in pixels.
frameborderCDATA(Netscape only) If value is no, then no border is drawn.
hiddenCDATA(Netscape only) Accepts a value of true or false. Plugin is not displayed if false.
paletteCDATA(Netscape for Windows only) Specifies whether the plugin should use the foreground or background palette. May have a value of foreground or background.
altCDATA(Explorer only) Alternative text to the element.
alignCDATAAlignment or floating of object, as per the img element
widthlengthWidth of Object.
heightlengthHeight of Object.
unitsCDATA Units for the width and height attributes, may be pixels (px) or ems (em).
hspacepixelsHorizontal space between object and surroundings.
vspacepixelsVertical space between object and surroundings.

Details

Contained in:%flow
Contains:Empty
Start tag:Required
End tag:Forbidden

The embed element is a proprietary element that is a precursor to the object element. It is obvious that both Netscape and Explorer have based their implementation of object around embed, and the two elements have the same attributes supported by the two browsers. As with object, Navigator doesn't like it if you don't explicitly specify the height and width attributes, and the only difference here is that the Explorer implementation works relatively well. Navigator supports automatic information about a relevant plugin and even automatic installation of the plugin via the pluginspace and pluginurl attributes. Explorer supports the embedding of Java Applets using the embed element, but it is recommended that you use the applet element instead.

noembed (Explorer) (Netscape)

Attributes

AttributeTypeDescription

Details

Contained in:%flow
Contains:%flow
Start tag:Required
End tag:Required

The noembed element's contents are ignored by Netscape and Explorer, and the point is to provide alternative content for browsers that don't support the embed element.

multicol (Netscape)

Attributes

AttributeTypeDescription
colsNumberNumber of columns
gutterPixelsDistance between columns
widthPixelsWidth of each column

Details

Contained in:%flow
Contains:%flow
Start tag:Required
End tag:Required

The multicol element's contents are formatted into equally- sized columns by Navigator. It is useful to note that multicol elements can be nested to create mutliple columns within other columns. The content within the columns will be distributed between columns in order to make all columns approximately the same height.

spacer (Netscape)

Attributes

AttributeTypeDescription
typeCDATAType of spacer. Possible values are horizontal, vertical and block.
sizelengthSize of horizontal or vertical spacer.
widthlengthWidth of block spacer.
heightlengthHeight of block spacer.
alignCDATAAlignment or floating of block spacer, as per the img element

Details

Contained in:%flow
Contains:Empty
Start tag:Required
End tag:Forbidden

The spacer is the last of the ugly solutions to create space and margins in HTML documents, and should generally be avoided with stylesheets being preferred instead. It has three forms. type=horizontal creates a space between characters, as wide as the size attribute dictates. type=vertical creates a line break and adds a space as high as the size attribute dictates before continuing the document on a new line. type=block creates what is esentially an invisible image, which can be aligned or floated just like an image can, and must have width and height attributes that specify the size of the spacer. In this case the size attribute is ignored.

nobr (Explorer) (Netscape)

Attributes

AttributeTypeDescription

Details

Contained in:%flow
Contains:%flow
Start tag:Required
End tag:Required

The nobr element is used to disable word-wrapping. Long lines contained in a nobr element are not automatically wrapped, creating the potential for very long lines where the user has to scroll horizontally to see the whole line. To insert linebreaks within nobr elements, use the wbr element

wbr (Explorer) (Netscape)

Attributes

AttributeTypeDescription

Details

Contained in:nobr
Contains:Empty
Start tag:Required
End tag:Forbidden

The wbr element is used to tell the browser where a line break may occur within a nobr element. The line is not necessarily broken at that point, but if the contents of the nobr element do not fit inside the parent element and have to be line-wrapped, linebreaks will occur only where wbr elements occur. The following example illustrates this:

<nobr>
<p>Small <wbr> lines <wbr> like this do not have to be broken.
<p>Excruciatingly longer lines like this one you are reading right now
often do have to be broken, and when they finally exceed the width of
the screen the browser tries to find a wbr element in order <wbr> to
break the line.
</nobr>

Use of the wbr element is discouraged along with use of the nobr element. The cases where a linebreak need to be avoided are rare, and the non-breaking space character can be used for the same purpose to achieve the same effect.

blink (Netscape)

Attributes

AttributeTypeDescription

Details

Contained in:%inline or %flow
Contains:%inline or %flow
Start tag:Required
End tag:Required

blink is by far and without a doubt the most hated proprietary element ever created. Anything contained in this element will blink on and off in Netscape, creating an effect that might seem useful at first, but gets annoying pretty fast. Do not use this element, ever. If you really want something to blink, then I suggest you think it over and still not use this element.

xmp (Explorer) (Netscape)

Attributes

AttributeTypeDescription

Details

Contained in:%flow
Contains:%flow
Start tag:Required
End tag:Required

xmp was used to show text as it was written in the document, but its use is no longer recommended and it has been removed from the newer HTML specifications. Anything contained within an xmp element will be rendered as is, including text that would otherwise be interpreted as tags and character references, as in a fixed-width font. It is recommended that you use the pre element instead.

listing (Explorer) (Netscape)

Attributes

AttributeTypeDescription

Details

Contained in:%flow
Contains:%flow
Start tag:Required
End tag:Required

The listing element is also no longer included in HTML specifications. It is functionally equivalent to the pre element and displayes its contents in fixed-width, small font.

plaintext (Explorer) (Netscape)

Attributes

AttributeTypeDescription

Details

Contained in:%flow
Contains:Empty
Start tag:Required
End tag:Forbidden

The plaintext element is another element no longer included in the specifications. All content after a plaintext element is rendered as-is, as if it was contained in an xmp element. Its use is highly discouraged and it is very rarely useful.

keygen (Netscape)

Attributes

AttributeTypeDescription
nameNameForm control name
challengeCDATAChallenge string for generated key.

Details

Contained in:form
Contains:empty
Start tag:Required
End tag:Forbidden

The keygen element is a form control supported by Netscape that generates a public/private encryption key pair and sends the public key along with the form as the value of the control. It is rendered as a drop-down list from which the user can select an encryption strength, depending on his browsers capabilities.

layer, ilayer (Netscape)

Attributes

AttributeTypeDescription
leftpixels Horizontal position of inflow layer.
toppixels Vertical position of inflow layer.
pagexpixelsHorizontal position of layer relative to window.
pageypixelsVertical position of layer relative to window.
srcURIURI of HTML document containing layer's contents.
z-indexnumber Stacking order of layer .
aboveidrefIndicates that the layer should be positioned above the specified layer.
belowidrefIndicates that the layer should be positioned below the specified layer.
widthlengthWidth of layer.
heightlengthHeight of layer.
clipCDATA A string containing four comma-separated pixel positions that form a rectangle in the layer that is displayed .
visibilityCDATA A value of show displays the layer (default). A value of hidden hides the layer. A value of inherit indicates the layer has the same visibility as its parent layer.
bgcolorcolorBackground color.
backgroundURIURI of background image for layer.

Details

Contained in:%flow
Contains:%flow
Start tag:Required
End tag:Required

The layer and ilayer elements are used to position or clip a part of your document or an external document and display it. The layer element positions itself absolutely relative to the window or its parent layer, while the ilayer positions itself relative to the position its content would have had if the layer was absent. The content of the element is used unless the src attribute is present, in which case the contents of the document indicated by the value of the attribute is used, and the contents of the layer element are not displayed.

The same effect can be achieved using CSS2 in a manner consistent with the HTML 4.0 specification and compatible with Explorer, so the use of layers is strongly discouraged.

nolayer (Netscape)

Attributes

AttributeTypeDescription

Details

Contained in:%flow
Contains:%flow
Start tag:Required
End tag:Required

The nolayer element's contents are ignored by Netscape, in order to provide alternative content for browsers that do not support layers. If you are using layers in your pages, remember that browsers that follow the specification's recommendations on unrecognised tags will display the contents of a layer element, so a nolayer element may not be necessary.

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Stephanos Piperoglou, 19, is currently an undergraduate student of Computer Science in St. John's College, Cambridge University in England. He was born and has lived most of his life in Athens, Greece, where he has worked as a System Administrator for Greece's largest ISP, a Systems Analyst and, more recently, as a professional Web Designer at the Democritos National Centre for Scientific Research. He can be reached at SP249@hermes.cam.ac.uk.

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Created: Mar. 12, 1998
Revised: November 15, 2004