Proprietary 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
| Attribute | Type | Description |
|---|
| src | URI | URI of the sound to be played
|
| loop | Number | Number of times the sound should be
repeated
|
| volume | Signed Number | Volume of sound to be
played. Range is -10000 (lowest) to 0 (highest).
|
| balance | Signed Number | Left/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
| Attribute | Type | Description |
|---|
| behavior | CDATA | Behaviour of the marquee. May be
alternate, scroll or slide.
|
| direction | CDATA | Direction in which the marquee
should move. May be up, down, left or
right.
|
| loop | number | Number of times marquee should loop.
|
| scrollamount | number | Number of pixels marquee
should advance per step.
|
| scrolldelay | number | Number of milliseconds of
delay between steps.
|
| truespeed | boolean | Prevents rounding of
scrolldelay values of less than 60 to 60.
|
| bgcolor | color | Background color.
|
| height | length | Height of Marquee. Percentages
refer to screen height.
|
| width | length | Width of Marquee.
|
| hspace | pixels | Horizontal space between marquee
and surroundings.
|
| vspace | pixels | Vertical 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
| Attribute | Type | Description |
|---|
| src | URI | URI of object to be displayed
|
| code | URI | (Explorer only) URI of an embedded applet
|
| codebase | URI | (Explorer only) Base URI for embedded applet
|
| pluginspace | URI | (Netscape only) URI for
instructions for installing the plug-in required by the object
|
| pluginurl | URI | (Netscape only) URI for a Java
Archive (JAR) which contains an installable version of the plugin.
|
| border | pixels | (Netscape only) Border width in
pixels.
|
| frameborder | CDATA | (Netscape only) If value is
no, then no border is drawn.
|
| hidden | CDATA | (Netscape only) Accepts a value of
true or false. Plugin is not displayed if
false.
|
| palette | CDATA | (Netscape for Windows only)
Specifies whether the plugin should use the foreground or background
palette. May have a value of foreground or background.
|
| alt | CDATA | (Explorer only) Alternative text to the element.
|
| align | CDATA | Alignment or floating of object, as
per the img element
|
| width | length | Width of Object.
|
| height | length | Height of Object.
|
| units | CDATA |
Units for the width and height attributes, may be
pixels (px) or ems (em). |
| hspace | pixels | Horizontal space between object
and surroundings.
|
| vspace | pixels | Vertical 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
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
| Attribute | Type | Description |
|---|
| cols | Number | Number of columns
|
| gutter | Pixels | Distance between columns
|
| width | Pixels | Width 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
| Attribute | Type | Description |
|---|
| type | CDATA | Type of spacer. Possible values are
horizontal, vertical and block.
|
| size | length | Size of horizontal or vertical
spacer.
|
| width | length | Width of block spacer.
|
| height | length | Height of block spacer.
|
| align | CDATA | Alignment 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
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
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
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
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
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
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
| Attribute | Type | Description |
|---|
| name | Name | Form control name
|
| challenge | CDATA | Challenge 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
| Attribute | Type | Description |
|---|
| left | pixels |
Horizontal position of inflow layer. |
| top | pixels |
Vertical position of inflow layer. |
| pagex | pixels | Horizontal position of layer
relative to window.
|
| pagey | pixels | Vertical position of layer relative
to window.
|
| src | URI | URI of HTML document containing layer's
contents.
|
| z-index | number |
Stacking order of layer . |
| above | idref | Indicates that the layer should be
positioned above the specified layer.
|
| below | idref | Indicates that the layer should be
positioned below the specified layer.
|
| width | length | Width of layer.
|
| height | length | Height of layer.
|
| clip | CDATA |
A string containing four comma-separated pixel positions that form a
rectangle in the layer that is displayed . |
| visibility | CDATA |
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. |
| bgcolor | color | Background color.
|
| background | URI | URI 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
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.
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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