HTML 文档中的容器

在 HTML 中,� OBJECT 元素指定了渲染结构的位置以及渲染结构需的数据的位置. 这些特性通过 OBJECT 元素的信息来指定. PARAM 元素指一个动行态值的集. 我们在后面研究这个元素, 在物件初始化部分.

一个用户代理器必须根据下列的优先权法则来解译 OBJECT 元素:

在下面的例� 程中, 我们插入了一个虚构的以 Python (大蟒) 语言写的渲染结构来显示一个电脑时钟. 这个可通行程� 式无需额外的数据和运行态值. classid 特性指定小运行程式的位置:

牋牋
<OBJECT classid="http://www.miamachina.it/analogclock.py">
</OBJECT>

我们建议通过包含 OBJECT 内容中的交互文字来完成这个声明. 此例中用户代理器无法渲染这个钟.

牋牋
<OBJECT classid="http://www.miamachina.it/analogclock.py">
An animated clock.
</OBJECT>

注意用户代理器将在解译 OBJECT 声明的同时渲染这个种. 在物件第一次声明时渲染结构可能会延迟 (在下描述).

在下面的例程中, 我们嵌入数个 OBJECT 声明来举例说明渲染工作. 用户代理器将尝� 试渲� 染它能够的第一个 OBJECT 元素, 通过下面的次序: (1) 一个用 Python (大蟒) 语言写的地球小运行程式, (2) 一个地球的 MPEG 动画, (3) 一个地球的 GIF 图像, (4) 交互文本

<OBJECT title="The Earth as seen from space"
牋牋牋牋牋 classid="http://www.observer.mars/TheEarth.py">
�<OBJECT data="TheEarth.mpeg" type="application/mpeg">
� <OBJECT src="TheEarth.gif">
牋 The <STRONG>Earth</STRONG> as seen from space.
� </OBJECT>
�</OBJECT>
</OBJECT>

外部声明指定一个小运行程式不需要数据和初始值. 第二个声明指明一个 MPEG 电影并且由于没有定义一个渲染结构, 它依靠用户代理器来处理这个动画. 我们还设置了内层与外部数据的比较. 被渲染的数据可以通过两种途径来指定: 内层和和来自于外部资源的. 形成方法通常将引起更快速� 的渲染, 但在渲染大量数据时却是不相宜的. 物件初始化:�PARAM 元素 <!ELEMENT PARAM - O EMPTY牋牋牋 -- named property value --> <!ATTLIST PARAM � name牋牋牋� CDATA牋牋� #REQUIRED -- property name -- � value牋牋牋 CDATA牋牋� #IMPLIED� -- property value -- � valuetype (DATA|REF|OBJECT) DATA -- How to interpret value -- � type牋牋牋� CDATA牋牋� #IMPLIED� -- Internet media type -- � > 开始标记: 需要, 结束标记: 禁止

特性定义

name = value = valuetype = data|ref|object: 这个特性指出 value 特性的形式. 可能的值为:
type = valuetype 只有在 特性被定义为 "ref" 时,� 此特性指定了由 value 特定指资源的互联网媒体形式 (参见

PARAM 元素指定一个可被运行时渲染结构的设置组. 任意数量的 PARAM 元素可以出现于一个 OBJECT 声明的开始部分. 名称和值的语法假定能够被渲染结构理解. 名称和值通过标准输入传送给渲染机制.

我们回到我们的钟例程. 这次, 我们假定渲染机制 (钟) 能够处理两个定义初始高度和宽度的运行态参数. 我们通过初始的两个 PARAM 元素来设定一个 40x40 的长方形.

牋牋 <OBJECT classid="http://www.miamachina.it/analogclock.py"> <PARAM name="height" value="40" valuetype="data"> <PARAM name="width" value="40" valuetype="data"> This user agent cannot render Python apps. </OBJECT>
Since the default valuetype for a PARAM element is "data", we could replace the above declarations with either:
� <PARAM name="height" value="40"> <PARAM name="width" value="40" >
or:
� <PARAM name="height" value="40" data> <PARAM name="width" value="40"� data>
(The latter form -- the value "data" only for valuetype attribute -- is possible due to the DTD definition of this attribute.)

In the following example, run-time data for the rendering mechanism's "Init_values" parameter is specified as an external resource (a GIF file). The value of the valuetype attribute is thus set to "ref", and the value is a URL designating the resource.
<OBJECT classid="http://www.gifstuff.com/gifappli" 牋牋牋 standby="Loading Elvis..."> <PARAM name="Init_values" 牋牋牋 value="./images/elvis.gif"> 牋牋牋 valuetype="ref"> </OBJECT>
Note that we have also set the standby attribute so that the user agent may render a message while the rendering mechanism loads.
Rendering mechanisms are located by URLs. As we discussed in the section on URLs, the first segment of an absolute URL specifies the protocol used to transfer the data designated by the URL. For HTML documents, this protocol is generally "http". Some rendering mechanisms might employ other protocols. For instance, when specifying a Java rendering mechanism, you may use URLs that begin with "java" and for ActiveX applets, you may use "clsid".
In the following example, we insert a Java applet into an HTML document.
<OBJECT classid="java:program.start"> </OBJECT>
By setting the codetype attribute, a user agent can decide whether to retrieve the Java application based on its ability to do so.
<OBJECT codetype="application/octet-stream" 牋牋牋牋牋 classid="java:program.start"> </OBJECT>
Some rendering schemes require additional information to identify their implementation and must be told where to find that information. You may give path information to the rendering mechanism via the codebase attribute.
<OBJECT codetype="application/octet-stream" 牋牋牋牋牋 classid="java:program.start"> 牋牋牋牋牋 codebase="http://foooo.bar.com/java/myimplementation/" </OBJECT>

The following example specifies (with the classid attribute) an ActiveX rendering mechanism via a URL that begins with the protocol information "clsid". The data attribute locates the data to render (another clock).
<OBJECT classid="clsid:663C8FEF-1EF9-11CF-A3DB-080036F12502" 牋牋牋牋牋 data="http://www.acme.com/ole/clock.stm"> This application is not supported. </OBJECT>

Object declarations and instantiations
The preceding examples have only illustrated isolated object definitions. When a document is to contain more than one instance of the same object, it is possible to separate the declaration of the object from its instantiations. Doing so has several advantages:

Data may be retrieved from the network by the user agent one time (during the declaration) and reused for each instantiation.

It is possible to instantiate an object from a different location in the document, for example, by activating a link.

It is possible to specify objects as run-time data for other objects.

To declare an rendering mechanism so that it is not executed when read by the user agent, set the boolean declare attribute in the OBJECT element. At the same time, you must identify the declaration by setting the id attribute in the OBJECTelement to a unique value. Later instantiations of the object will refer to this identifier.
A rendering mechanism defined with the declare attribute is instantiated every time the OBJECT is referenced thereafter.
In the following example, we declare an OBJECT and cause it so be instantiated by referring to it from a link. Thus, the object can be activated by clicking on some highlighted text, for example.
<OBJECT declare 牋牋牋牋牋 id="earth_declaration"� 牋牋牋牋牋 data="TheEarth.mpeg"� 牋牋牋牋牋 type="application/mpeg"> � <OBJECT src="TheEarth.gif"> 牋 The <STRONG>Earth</STRONG> as seen from space. � </OBJECT> </OBJECT> ...later in the document... Click to see a neat <A href="#earth_declaration"> animation of The Earth!</A>

The following example illustrates how to specify run-time values that are other objects. In this example, we send text (a poem, in fact) to a hypothetical mechanism for viewing poems. The rendering mechanism recognizes a run-time parameter named "font" (say, for rendering the poem text in a certain font). The value for this parameter is itself an object that inserts (but does not render) the font object. The relationship between the font object and the poem viewer object is achieved by (1) assigning the id "tribune" to the font object declaration and (2) referring to it from the PARAM element of the poem viewer object (with valuetype and value).
<OBJECT declare 牋牋 id="tribune" 牋牋 type="application/x-webfont" 牋牋 data="tribune.gif"> </OBJECT> ...view the poem in KublaKhan.txt here... <OBJECT classid="http://foo.bar.com/poem_viewer"� 牋牋牋牋牋 data="KublaKhan.txt"> <PARAM name="font" valuetype="object" value="#tribune"> <P>You're missing a really cool poem viewer ... </OBJECT>

User agents that don't support the declare attribute must render the contents of the OBJECT declaration.
Object alignment
The align attribute has been deprecated for this element in favor of style sheets.
The align attribute specifies the position of an object with respect to its context.
The following values place an object in the heart of text:

texttop: means the top of the object should be vertically aligned with the top of the current text line.

middle: means the middle of the object should be vertically aligned with the current baseline.

textmiddle: means the middle of the object should be vertically aligned with the position midway between the baseline and the x-height for the current font. The x-height is defined as the top of a lower case x in Western writing systems. If the text font is an all-caps style, user agents should use the height of a capital X. For other writing systems, user agents should align the middle of the object with the middle of the text.

baseline: means the bottom of the object should be vertically aligned with the current baseline.

textbottom: means the bottom of the object should be vertically aligned with the bottom of the current text line.

Three other values, left, center, and right, cause an object to float. They are discussed in the section on Including an image: the�IMG element
 <!ELEMENT IMG - O EMPTY牋牋� --� Embedded image --> <!ATTLIST IMG � %attrs;牋牋牋牋牋牋牋牋牋牋牋牋� -- %coreattrs, %i18n, %events -- � src牋牋牋牋 %URL牋牋牋 #REQUIRED -- URL of image to embed -- � alt牋牋牋牋 CDATA牋牋� #IMPLIED� -- description for text only browsers -- � align牋牋牋 %IAlign牋� #IMPLIED� -- vertical or horizontal alignment -- � height牋牋� %Pixels牋� #IMPLIED� -- suggested height in pixels -- � width牋牋牋 %Pixels牋� #IMPLIED� -- suggested width in pixels -- � border牋牋� %Pixels牋� #IMPLIED� -- suggested link border width -- � hspace牋牋� %Pixels牋� #IMPLIED� -- suggested horizontal gutter -- � vspace牋牋� %Pixels牋� #IMPLIED� -- suggested vertical gutter -- � usemap牋牋� %URL牋牋牋 #IMPLIED� -- use client-side image map -- � ismap牋牋牋 (ismap)牋� #IMPLIED� -- use server-side image map -- � >
Start tag: required, End tag: forbidden
Attribute definitions
�
src = align = bottom|middle|top|left|right

Deprecated. This attribute specifies the position of the image with respect its surrounding context. Its values are explained in the section on image alignment.

Attributes defined elsewhere

id, class (document-wide identifiers)

alt (alternate text)

lang (language information), dir (text direction)

title (element titles)

style (inline style information)

onclick, ondblclick, onmousedown, onmouseup, onmouseover, onmousemove, onmouseout, onkeypress, onkeydown, onkeyup (intrinsic events)

ismap, usemap (client side image maps)

name (border, hspace, vspace (visual presentation of objects, images, and applets)

The IMG element embeds an image in the current document at the location of the element's definition. However, we recommend using the OBJECT element to insert an image into a document.
The height and width attributes of this element override the natural height and width of the source image. User agents should scale the image appropriately.
In an earlier example, we defined a link to a family photo. Here, we insert the photo directly into the current document
...preceding text... I just returned from vacation! Here's a photo of my family at the lake: <IMG src="http://www.somecompany.com/People/Ian/vacation/family.png" 牋牋 alt="A photo of my family at the lake.">
This may be expressed with the OBJECT element as follows:
...preceding text... I just returned from vacation! Here's a photo of my family at the lake: <OBJECT data="http://www.somecompany.com/People/Ian/vacation/family.png" 牋牋牋� type="image/png"> A photo of my family at the lake. </OBJECT>

The alt attribute specifies alternate text when the image cannot be displayed (see below for information on how to specify alternate text ).
Image alignment
The align attribute has been deprecated for this element in favor of style sheets.
The align attribute specifies the position of an object with respect to its context.
The following values place an object in the heart of text:

bottom: means that the bottom of the image should be vertically aligned with the current baseline. This is the default value.

middle: means that the center of the image should be vertically aligned with the current baseline.

top: means that the top of the image should be vertically aligned with the top of the current text line.

Two other values, left and right, cause the image to float. They are discussed in the section on Differing interpretations of align. Existing user agents vary in their interpretation of the align attribute. Some only take into account what has occurred on the text line prior to the element, some take into account the text on both sides of the element.

Including an applet: the�APPLET element
APPLET is deprecated.
<!ELEMENT APPLET - - (PARAM | %inline)*> <!ATTLIST APPLET � codebase牋� %URL牋牋牋 #IMPLIED牋 -- optional base URL for applet -- � archive牋牋 CDATA牋牋� #IMPLIED牋 -- comma separated archive list -- � code牋牋牋� CDATA牋牋� #IMPLIED牋 -- applet class file -- � object牋牋� CDATA牋牋� #IMPLIED牋 -- serialized applet file -- � alt牋牋牋牋 CDATA牋牋� #IMPLIED牋 -- description for text only browsers -- � name牋牋牋� CDATA牋牋� #IMPLIED牋 -- allows applets to find each other -- � width牋牋牋 %Pixels牋� #REQUIRED� -- suggested width in pixels -- � height牋牋� %Pixels牋� #REQUIRED� -- suggested height in pixels -- � align牋牋牋 %IAlign牋� #IMPLIED牋 -- vertical or horizontal alignment -- � hspace牋牋� %Pixels牋� #IMPLIED牋 -- suggested horizontal gutter -- � vspace牋牋� %Pixels牋� #IMPLIED牋 -- suggested vertical gutter -- � >
Start tag: required, End tag: required
Attribute definitions
�
codebase = code = name = width = height = align = bottom|middle|top|left|right

This attribute specifies the position of the object with respect to its surrounding context. Its values are explained in the section on image alignment.

archive = codebase. Preloading resources can significantly improve the performance of applets.
object = Attributes defined elsewhere

alt (alternate text)

hspace, vspace (visual presentation of objects, images, and applets)

This element, supported by all Java-enabled browsers, allows designers to embed a Java applet in an HTML document. It has been deprecated in favor of the OBJECT element.
The content of the APPLET acts as alternate information for user agents that don't support this element or are currently configured not to support applets. The content must be ignored otherwise.
The following sample Java applet:
<APPLET code="Bubbles.class" width="500" height="500"> Java applet that draws animated bubbles. </APPLET>
may be rewritten as follows with OBJECT:
<OBJECT codetype="application/octet-stream" 牋牋牋� classid="java:Bubbles.class" 牋牋牋� width="500" height="500"> Java applet that draws animated bubbles. </OBJECT>

Initial values may be supplied to the applet via the PARAM element.
The following sample Java applet:
<APPLET code="AudioItem" width="15" height="15"> <PARAM name="snd" value="Hello.au|Welcome.au"> Java applet that plays a welcoming sound. </APPLET>
may be rewritten as follows with OBJECT:
<OBJECT codetype="application/octet-stream" 牋牋牋� classid="AudioItem"� 牋牋牋� width="15" height="15"> <PARAM name="snd" value="Hello.au|Welcome.au"> Java applet that plays a welcoming sound. </OBJECT>

Including HTML in another HTML document
Sometimes, rather than linking to another document, it is helpful to include the contents of an HTML document in another HTML document. We recommend using the OBJECT element with the data attribute for this purpose.
For instance, the following line will include the contents of piece_to_include.html at the location where the OBJECT definition occurs.
...text before... <OBJECT data="file_to_include.html"> Warning: file_to_include.html could not be included. </OBJECT> ...text after...
The contents of OBJECT must only be rendered if the file specified by the data attribute cannot be loaded.
The behavior of a user agent in cases where a file includes itself is not defined.
Careful file inclusions. Be careful if you attempt to include a section of an HTML document defined by an anchor. The entire document after the anchor definition will be included, and you might unwittingly include unwanted end tags (for elements such as BODY, HTML, etc.) in your document.
The IFRAME element may also be used to insert an inline frame containing text in an HTML document.
Including an image map in an HTML document
An image map allows users authors to specify active regions of an image or object and assign a specific action to each region (e.g., retrieve a document, run a program, etc.)
An image map is created by associating an object with a specification of sensitive geometric areas on the object.
There are two types of image maps:

Server-side. When a user activates a region of a server-side image map with a mouse, the pixel coordinates of the click are sent to the server where the document is housed. The server interprets the coordinates and performs some action.

Client-side. When a user activates a region of a client-side image map with a mouse, the pixel coordinates are interpreted by the user agent. The user agent selects a link that was specified for the activated region and follows it.

Client-side image maps are preferred over server-side image maps. It is possible to implement client-side image maps with several elements.
Non-graphical representation of image maps. Non-graphical user agents may render client-side image maps as sets of textual links. The textual region may be activated by keyboard input.

Client-side image maps
The following attributes are defined for several elements (A and AREA). They allow authors to specify a set of geometrical regions and associate URLs with them.
Attribute definitions
�
shape = default|rect|circle|poly

This attribute specifies the shape of a region. Possible values:

default: Specifies the entire region.

rect: Define a rectangular region.

circle: Define a circular region.

poly: Define a polygonal region.

coords = length-list

This attribute specifies the position a shape on the screen. The number and order of values depends on the shape being defined. Possible combinations:

rect: left-x, top-y, right-x, bottom-y.

circle: center-x, center-y, radius.

poly: x1, y1, x2, y2, ..., xN, yN.

Coordinates are relative to the top, left corner of the object. All values are OBJECT element.
Attribute definitions
�
shapes

When set, this boolean attribute specifies that the object being defined is an image map. The contents of the OBJECT element will specify the active regions.

In the following example, we create a client-side image map for the OBJECT element by associating URLs with regions specified by a series of A elements.
<OBJECT data="navbar.gif" shapes> �<A href="guide.html" shape="rect" coords="0,0,118,28">Access Guide</a> | �<A href="shortcut.html" shape="rect" coords="118,0,184,28">Go</A> | �<A href="search.html" shape="circ" coords="184,200,60">Search</A> | �<A href="top10.html" shape="poly" coords="276,0,373,28,50,50,276,0">Top Ten</A> </OBJECT>

If the OBJECT element includes a shapes attribute, user agents must parse the contents of the element to look for anchors.
If two or more defined regions overlap, the region defined first takes precedence (i.e., responds to user input).
Client-side image maps with�MAP and�AREA
The MAP and AREA elements provide an alternate mechanism for client side image maps.
<!ELEMENT MAP - - (AREA)*> <!ATTLIST MAP � %coreattrs;牋牋牋牋牋牋牋牋牋牋� -- id, class, style, title -- � name牋牋牋� CDATA牋牋 #IMPLIED � >
Start tag: required, End tag: required
<!ELEMENT AREA - O EMPTY> <!ATTLIST AREA � shape牋牋牋 %Shape牋� rect牋牋� -- controls interpretation of coords -- � coords牋牋� %Coords牋 #IMPLIED� -- comma separated list of values -- � href牋牋牋� %URL牋牋� #IMPLIED� -- this region acts as hypertext link -- � target牋牋� CDATA牋牋 #IMPLIED� -- where to render linked resource --� � nohref牋牋� (nohref)� #IMPLIED� -- this region has no action -- � alt牋牋牋牋 CDATA牋牋 #REQUIRED -- description for text only browsers -- � tabindex牋� NUMBER牋� #IMPLIED� -- position in tabbing order -- � >
Start tag: required, End tag: forbidden
Attribute definitions
�
nohref

When set, this boolean attribute specifies that a region has no associated link.

Attributes defined elsewhere

id, class (document-wide identifiers)

lang (language information), dir (text direction)

title (element titles)

style (inline style information)

name (alt (alternate text)

href ( anchor reference) target (frame target information)

tabindex (tabbing navigation)

accesskey (access keys)

shape, coords (image maps)

Several elements (OBJECT, IMG, and INPUT) allow the following attribute to specify an associated client-side image map.
Attribute definitions
�
usemap = MAP and AREA.

We can rewrite the previous example in terms of MAP and AREA. We still create an OBJECT that will insert an image. We associate the object and the image map by setting the usemap attribute on the OBJECT and the name attribute of the MAP element to the same value.
<OBJECT data="navbar1.gif" usemap="#map1"></OBJECT> <MAP name="map1"> �<AREA href="guide.html"� 牋牋牋牋� alt="Access Guide"� 牋牋牋牋� shape="rect"� 牋牋牋牋� coords="0,0,118,28"> �<AREA href="search.html"� 牋牋牋牋� alt="Search"� 牋牋牋牋� shape="rect"� 牋牋牋牋� coords="184,0,276,28"> �<AREA href="shortcut.html"� 牋牋牋牋� alt="Go"� 牋牋牋牋� shape=circ� 牋牋牋牋� coords="184,200,60"> �<AREA href="top10.html"� 牋牋牋牋� alt="Top Ten"� 牋牋牋牋� shape="poly"� 牋牋牋牋� coords="276,0,373,28,50,50,276,0"> </MAP>
The alt attribute specifies alternate text for cases when the image map may not be displayed (see below for information on how to specify alternate text).

Note: MAP is not backwards compatible with HTML 2.0 user agents.

Server-side image maps
Server-side image maps may be interesting in cases where the image map is too complicated for a client-side image map.
It is only possible to define a server-side image map with the IMG element. To do so, set the boolean attribute�ismap in the IMG definition. The associated map of regions must be specified with the usemap attribute.
When the user activates a region of the image map, the screen coordinates are sent directly to the server where the document resides. Screen coordinates are expressed as screen pixel values. For normative information about the definition of a pixel and how to scale it, please consult [CSS1].
The location clicked is passed to the server as follows. The user agent derives a new URL from the URL specified by the href attribute by appending `?' followed by the x and y coordinates, separated by a comma. The link is then followed using the new URL. For instance, in the previous example, if the user clicks at at the location x=10, y=27 then the derived URL is "/cgibin/navbar.map?10,27".
In the following example, the first active region defines a client-side link. The second defines a server-side link, but doesn't assign a specific shape to it (this is accomplished with the "default" value of the shape attribute). Since the regions of the two links overlap, the first takes precedence of the later definition. Thus, a click anywhere but in the rectangle will cause the click's coordinates to be sent to the server.
<OBJECT data="game.gif" shapes> � <A href="guide.html" shape="rect" coords="0,0,118,28"> 牋牋牋� Rules of the Game</A> � <A href="http://www.acme.com/cgi-bin/competition" 牋牋牋� ismap� 牋牋牋� shape="default"> 牋牋牋� Guess the location</a> </OBJECT>

Visual presentation of images, objects, and applets
All IMG and OBJECT attributes that concern visual alignment or presentation have been deprecated in favor of style sheets.
The height and width attributes give user agents an idea of the size of an image or object so that they may reserve space for it and continue rendering the document while waiting for the image data. Both attributes take values of type length.
Images or objects that are the content of an A element are sometimes surrounded by a border. The border attribute specifies the width of this border.
How to specify alternate text

Attribute definitions
�
alt = lang attribute.

Several non-textual elements (IMG, AREA, APPLET, and INPUT) allow authors to specify alternate text to serve as content when the element cannot be rendered normally. Specifying alternate text assists users without graphic display terminals, users whose browsers don't support forms, visually impaired users, those who use speech synthesizers, those who have configured their graphical user agents not to display images, etc.
While alternate text may be very helpful, it must be handled with care. Authors should observe the following guidelines:

Do not specify meaningless alternate text when including images intended to format a page. In this case, the alternate text should be the empty string (""). In any case, authors should not use images to format pages; style sheets should be used instead.

Do not specify meaningless alternate text (e.g., "dummy text"). Not only will this frustrate users, it will slow down user agents that must convert text to speech or braille output.

The alt attribute is mandatory for the AREA element, but optional for IMG, APPLET, and INPUT.
When an author does not set the alt attribute for the IMG or APPLET elements, user agents should supply the alternate text, calculated in the following order:

If the title has been specified, its value should be used as alternate text.

Otherwise, if HTTP headers provide title information when the included object is retrieved, this information should be used as alternate text.

Otherwise, if the included object contains text fields (e.g., GIF images contain some text fields), information extracted from the text fields should be used as alternate text. Since user agents may have to retrieve an entire object first in order to extract textual information, user agents may adopt more economical approaches (e.g., content negotiation).

Otherwise, in the absence of other information, user agents should use the file name (minus the extension) as alternate text.

When an author does not set the alt attribute for the INPUT element, user agents should supply the alternate text, calculated in the following order:

If the title has been specified, its value should be used as alternate text.

Otherwise, if the name has been specified, its value should be used as alternate text.

Otherwise (submit and reset buttons), the value of the type attribute should be used as alternate text.

前页牋后页牋目录牋元素牋特性�

容器

包含一个物件:`OBJECT` 元素

物件初始化:�`PARAM` 元素

Object declarations and instantiations

Object alignment

Image alignment

Including an applet: the�`APPLET` element

Including HTML in another HTML document

Including an image map in an HTML document

Client-side image maps

Client-side image maps with�`MAP` and�`AREA`

Server-side image maps

Visual presentation of images, objects, and applets

How to specify alternate text

容器

包含一个物件:OBJECT 元素

物件初始化:�PARAM 元素