W3C WD-object-970218

Inserting objects into HTML

W3C Working Draft 18-Feb-1997

This version:
Latest version:
Dave Raggett <dsr@w3.org>
Charlie Kindel, Microsoft Corporation
Lou Montulli, Netscape Communications Corp.
Eric Sink, Spyglass Inc.
Wayne Gramlich, Sun Microsystems
Jonathan Hirschman, Pathfinder
Tim Berners-Lee, W3C
Dan Connolly, W3C
Bruce Kahn, Iris Associates
Steve Byrne, JavaSoft

Status of This Document

This draft is work under review by the W3C HTML Working Group, for potential incorporation in an upcoming version of the HTML specification, code named Cougar. Please remember this is subject to change at any time, and may be updated, replaced or obsoleted by other documents. It is inappropriate to use W3C Working Drafts as reference material or to cite them as other than "work in progress".

A list of current W3C Working Drafts can be found at http://www.w3.org/pub/WWW/TR. This is work in progress and does not imply endorsement by, or the consensus of, either W3C or members of the HTML working group. Further information about Cougar is available at http://www.w3.org/pub/WWW/MarkUp/Cougar/.

Please send detailed comments to www-html-editor@w3.org. We cannot garantee a personal response, but summaries will be maintained off the Cougar page. Public discussion on HTML features takes place on www-html@w3.org. To subscribe send a message to www-html-request@w3.org with subscribe in the subject.

Previous Work

Previously this draft was known as the "INSERT" draft. However, on 13-Feb-96 the authors decided, with input from various parties, to rename the elements defined by the specification. Thus the document was renamed from WD-insert to WD-object.


The HyperText Markup Language (HTML) is a simple markup language used to create hypertext documents that are portable from one platform to another. HTML documents are SGML documents with generic semantics that are appropriate for representing information from a wide range of applications.

This specification extends HTML to support the insertion of multimedia objects including Java applets, Microsoft Component Object Model (COM) objects (e.g. ActiveX Controls and ActiveX Document embeddings), and a wide range of other media plug-ins. The approach allows objects to be specified in a general manner and provides the ability to override the default implementation of objects.



HTML 2.0 defined only a single mechanism for inserting media into HTML documents: the IMG element. While this element has certainly proved worthwhile, the fact that it is restricted to image media severely limits it usefulness as richer and richer media finds its way onto the Web.

Developers have been experimenting with ideas for dealing with new media: Microsoft's DYNSRC attribute for video and audio, Netscape's EMBED element for compound document embedding, and Sun's APP and APPLET elements for executable code.

Each of these proposed solutions attacks the problem from a slightly different perspective, and on the surface are each very different. In addition, each of these proposals falls short, in one way or another, of meeting the requirements of the Web community as a whole. However, we believe that this problem can be addressed with a single extension that addresses all of the current needs, and is fully extensible for the future.

This specification defines a new element <OBJECT> which subsumes the role of the IMG element, and provides a general solution for dealing with new media, while providing for effective backwards compatibility with existing browsers. OBJECT allows the HTML author to specify the data, and/or properties/parameters for initializing objects to be inserted into HTML documents, as well as the code that can be used to display/manipulate that data. Here, the term object is used to describe the things that people want to place in HTML documents, but other terms for these things are: components, applets, plug-ins, media handlers, etc.

The data can be specified in one of several ways: a file specified by a URL, in-line data, or as a set of named properties. In addition, there are a number of attributes that allow authors to specify standard properties such as width, and height. The code for the object is specified in several ways: by an explicit reference, or indirectly by the object's "class name" or media type.

This specification covers the syntax and semantics for inserting such objects into HTML documents, but leaves out the architectural and application programming interface issues for how objects communicate with the document and other objects on the same page. It is anticipated that future specifications will cover these topics, including scripting languages and interfaces.

An introduction to the OBJECT element

This section is intended to help readers get the feel of the insertion mechanism, and is not a normative part of the specification. The OBJECT element provides a richer alternative to the IMG element. It may be used when the author wishes to provide an alternative for user agents that don't support a particular media. A simple example of using OBJECT is:

    <OBJECT data=TheEarth.avi type="application/avi" alt="The Earth">
    <img src=TheEarth.gif alt="The Earth">

Here the user agent would show an animation if it supports the AVI format, otherwise it would show a GIF image. The IMG element is used for the latter as it provides for backwards compatibility with existing browsers. The TYPE attribute allows the user agent to quickly detect that it doesn't support a particular object, and avoid wasting time downloading it. Another motivation for using the TYPE attribute is when the object is loaded off a local drive, as it allows the format to be specified directly rather than being inferred from the file extension. The ALT attribute allows the user agent to provide an alternative to processing the OBJECT resource indicated by the DATA attribute.

A similar example for viewing a Macromedia Shockwave presentation, giving the intended width and height of the display area:

    <OBJECT data=shocknew.dcr
            width=288 height=200>
    <img src=shocknew.gif alt="Best with Shockwave">

The next example inserts an applet written in the Python language that displays a (rather large) analog clock. The CLASSID attribute gives a URL for the Python code implementing the applet. The PARAM element is used to pass named parameters to objects. Without <PARAM NAME=size VALUE=40>, the clock will measure only 200 pixels.

    <PARAM NAME=size VALUE=40>
    fall back ...

The following example is a Java applet. The CLASSID uses the java: URL scheme [Ref 5] to name the Java class program.start. The value for the missing CODEBASE attribute, used to locate the implementation, defaults to same base URL as the document. The "main" method in the class program.start is invoked to start the Java applet. Unlike the <APPLET> element, no ".class" is permitted at the end of the CLASSID.

      Your browser does not know how to execute Java applications.

In the next example, CODEBASE has been explicitly set, and an additional <PARAM> element has been provided. A browser can examine CODETYPE to determine whether or not to attempt to fetch the Java applet or go immediately to the apology section. It plays the same role for CLASSID as TYPE does for DATA.

    <PARAM NAME="options" VALUE="xqz">
        Your browser does not know how to execute Java applications.

Here is another clock, but this time using an ActiveX control:

    fall back ...

This uses the clsid: URL scheme [Ref 6] to specify the ActiveX class identifier. The ID attribute allows other controls on the same page to locate the clock. The DATA attribute points to data used to initialize the object's state. Note that ActiveX data streams include a class identifier that can be used by the ActiveX loader to find an implementation in the absence of the CLASSID attribute. The CODEBASE attribute can be used to give a URL as a hint to the ActiveX loader on where to find an implementation for this class.

For speedy loading of objects you can inline the object's state data using the URL data: scheme [Ref 4], e.g.

       data="data:application/x-oleobject;base64, ...base64 data..."
    fall back...

Inline data is only recommended for small amounts of data.

A walk through the DTD

The document type definition provides the formal definition of the allowed syntax for HTML inserts. The following is an annotated listing of the DTD defining the semantics of the elements and their attributes. The complete listing appears at the end of this document.

Standard Units for Lengths

Length values can be specified as an integer representing the number of screen pixels (the default), or as a percentage of the current displayable region, e.g. "50%", for widths, this is the space between the current left and right margins, while for heights, this is the height of the current window or table cell etc.

You can also use fixed units by including a suffix after a floating point number, e.g. "0.5in". The allowed suffices are: pt for points, pi for picas, in for inches, and cm for centimeters, where 72pt = 6pi = 1in = 2.54cm.

Note:For some attributes that take standard units, e.g. BORDER, some standard units do not always make sense, e.g. BORDER=10%. In these cases, the User Agent will do its best to interpret the value used.

Minimization of Attribute Values

HTML supports an SGML feature allowing minimization of attribute values.

  1. If the attribute value is a token consisting of only name characters (for HTML these are a-z, A-Z, 0-9 "-" and ".") then the quote marks may be omitted: <foo bar="baz"> is equivalent to <foo bar=baz>

  2. If the values are declared as a group of one or more names, then the attribute name can be omitted: <foo bar="baz"> is equivalent to <foo baz>

  3. Attribute names are always case insensitive. If the values are declared as a group of one or more names, the attribute value is case insensitive: <foo bar="baz"> is equivalent to <foo BaR=BaZ>

The above means that attributes such as DECLARE and SHAPES can be abbreviated to just the attribute value, i.e. declare="declare" is equivalent to declare, and to DECLARE. User agents must treat the permitted variant forms for attribute values as directly equivalent.

The OBJECT Element

The OBJECT element is used to insert an object into an HTML document. It requires both start and end tags. The OBJECT element has the same content model as the HTML BODY element, except that one or more optional PARAM elements can be placed immediately after the OBJECT start tag and used to initialize the inserted object. The content of the OBJECT element is rendered if the object specified by the CLASSID, CODEBASE and DATA attributes can't be rendered (user agents may choose to display the content of the OBJECT element or the OBJECT ALT attribute if displaying the actual element will take a long time to render). This provides for backwards compatibility with existing browsers, and allows authors to specify alternative media via nested OBJECT elements.

Note that this doesn't provide the same level of flexibility as would be provided by a richer description of resource variants. For instance when a resource in available are several media types and for each such type in English, Spanish, French and German.

<!ENTITY % OAlign "(texttop|middle|textmiddle|baseline|

<!ELEMENT OBJECT - - (PARAM | %body.content)*>
  %attrs                           -- id, class, style, lang, dir, title --
  declare     (declare)  #IMPLIED  -- declare but don't instantiate flag --
  classid     %URL       #IMPLIED  -- identifies an implementation --
  codebase    %URL       #IMPLIED  -- some systems need an additional URL --
  data        %URL       #IMPLIED  -- reference to object's data --
  type        CDATA      #IMPLIED  -- Internet content type for data --
  codetype    CDATA      #IMPLIED  -- Internet content type for code --
  standby     CDATA      #IMPLIED  -- message to show while loading --
  align       %OAlign    #IMPLIED  -- positioning inside document --
  height      %Length    #IMPLIED  -- suggested height --
  width       %Length    #IMPLIED  -- suggested width --
  border      %Length    #IMPLIED  -- suggested link border width --
  hspace      %Length    #IMPLIED  -- suggested horizontal gutter --
  vspace      %Length    #IMPLIED  -- suggested vertical gutter --
  usemap      %URL       #IMPLIED  -- reference to image map --
  shapes      (shapes)   #IMPLIED  -- object has shaped hypertext links --
  name        %URL       #IMPLIED  -- submit as part of form --
  alt         CDATA      #IMPLIED  -- textual alternative --
  tabindex    NUMBER     #IMPLIED  -- position in tabbing order --

In general, all attribute names and values in this specification are case insensitive, except where noted otherwise. OBJECT has the following attributes:

Used to define a document-wide identifier. This can be used for naming positions within documents for use as destinations of hypertext links. An ID attribute value is an SGML NAME token. NAME tokens are formed by an initial letter followed by letters in the range a-z and A-Z (no accented characters), digits, "-" and "." characters. It may also be used by the user agent or objects in the document to find and communicate with other objects embedded in the document.
Used to indicate that the object is to be declared but not instantiated. A detailed description of the DECLARE attribute is given below.
This is a URL that identifies an implementation for the object. In some object systems this is a class identifier.
Some URL schemes used to identify implementations require an additional URL to find the implementation. CODEBASE allows you to specify that URL. CODEBASE defaults to same base URL as the document if none is specified.
This is a URL pointing to the object's data, for instance a GIF file for an image. In the absence of the CLASSID attribute, the TYPE attribute is used to determine a default value for the CLASSID attribute. The implementation is then loaded as if the CLASSID attribute had been given explicitly.
This specifies the Internet Media Type [Ref 3] for the data referenced by the DATA attribute in advance of actually retrieving it. In the absence of the CLASSID attribute, this allows the user agent to retrieve the code implementing the object concurrently with the data, and to skip over unsupported media types without needing to make a network access.
This specifies the Internet Media Type [Ref 3] of the code referenced by the CLASSID attribute in advance of actually retrieving it. User agents may use the value of the CODETYPE attribute to skip over unsupported media types without needing to make a network access.
This allows you to specify a short text string the browser can show while loading the Object's implementation and data. It can include character entities for accented characters etc.
This determines where to place the object. The ALIGN attribute allows objects to be placed as part of the current text line, or as a distinct unit, aligned to the left, center or right.

The following values are chosen for their ease of implementation, and their independence of other graphics occurring earlier on the same line:

For ALIGN=TEXTTOP, the top of the object is vertically aligned with the top of the current font.

For ALIGN=MIDDLE, the middle of the object is vertically aligned with the baseline.

For ALIGN=TEXTMIDDLE, the middle of the object is 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 then use the height of a capital X. For other writing systems, align the middle of the object with the middle of the text.

For ALIGN=BASELINE, the bottom of the object is vertically aligned with the baseline of the text line in which the object appears.

For ALIGN=TEXTBOTTOM, the bottom of the object is vertically aligned with the bottom of the current font.

Note the proposed Netscape extensions for the align attribute of the IMG element are context sensitive, as are some of the implementations of ALIGN=TOP. See the test page at: http://www.w3.org/pub/WWW/MarkUp/Test/Img/imgtest.html
The following alignment values allow the object to float rather than being treated as part of the current line:

For ALIGN=LEFT, the object is floated down and over to the current left margin. Subsequent text is flowed past the right hand side of the visible area of the object.

For ALIGN=CENTER, the object is floated to after the end of the current line and centered between the left and right margins. Subsequent text starts at the beginning of the next line.

For ALIGN=RIGHT, the object is floated down and over to the current right margin. Subsequent text is flowed past the left hand side of the visible area of the object.

This gives the suggested width of a box enclosing the visible area of the object. The width is specified in standard units. User agents may use this value to scale an object to match the requested width if appropriate.

Smooth scaling a small image to a larger size provides an effective solution to reducing the time needed to download an image, offering better subjective results when compared to color reduction.

This gives the suggested height of a box enclosing the visible area of the object. The height is specified in standard units. User agents may use this value to scale an object to match the requested height if appropriate.
This attribute applies to the border shown when the object forms part of a hypertext link, as specified by an enclosing anchor element. The attribute specifies the suggested width of this border around the visible area of the object. The width is specified in standard units. For BORDER=0 no border should be shown. This is normally used when such a border would interfere with the visual affordances presented by the object itself. For instance, the object could render itself as a number of beveled buttons.
The suggested width of the space to the left and right of the box enclosing the visible area of the object. The width is specified in standard units. This attribute is used to alter the separation of preceding and following text from the object.
The suggested height of the space to the top and bottom of the box enclosing the visible area of the object. The height is specified in standard units.
This specifies a uniform resource locator for a client-side image map [Ref 2] in the format proposed by Spyglass Inc. This is normally appropriate only for static images.
The presence of this attribute indicates that the contents of the OBJECT element contains anchors with hypertext links associated with shaped regions on the visible area of the object. See below for further information.
This provides a way for user agents which support FORMs to determine whether an object within a FORM block should participate in the "submit" process. If NAME is specified and the DECLARE attribute is absent, then the user agent should include the value of the NAME attribute and data obtained from the object along with the information derived from other form fields. The mechanism used to obtain the object's data is specific to each object system.
This text is used in place of the referenced OBJECT, for example due to processing constraints or user preference.
Advisory title to be displayed as additional help when needed.

Note: As class identifiers in some object systems can be quite cumbersome, the CLASSID attribute may use a short URL to specify a class identifier indirectly. See Internet Draft on Hypertext link Relationships in HTML [Ref 1] for details on the "pointer" link relationship.

More Information About OBJECT DECLARE

OBJECT markup with the DECLARE attribute imply objects that are not created (instantiated) until needed by something that references them (i.e. late binding). Each such "binding" typically results in a separate copy of the object (this is class dependent). In other words, the OBJECT DECLARE is treated as a declaration for making an instance of an object.

If the declared object isn't supported, or fails to load, the user agent should try the content of the OBJECT DECLARE element, which is currently restricted to another OBJECT DECLARE element. The TYPE attribute can be used to specify the Internet Media Type for the object as a hint for this situation.

Examples of OBJECT DECLARE Usage

For instance:

    <OBJECT ID="obj1" DECLARE CLASSID=implementation CODEBASE=referenceURL >
    <PARAM NAME=param1 VALUE=value1>
    <PARAM NAME=param2 VALUE=value2>

    <P>This points to an <A HREF="#obj1">object</A>.

The meaning of the link in the anchor HREF="#obj1" depends on what it points at. In this case it points at an object declaration which is then used to replace the current page with a new instance of the specified object class and data. If the HREF points at an HTML element like <H1> or <P> or <A> then the browser scrolls the document to that point.

Note: Anchors can exploit nested declared objects to provide alternative media for a given resource.

The PARAM element

The PARAM element allows a list of named property values (used, for example, to initialize a ActiveX control, plug-in module or Java applet) to be represented as a sequence of PARAM elements. Note that PARAM is an empty element and should appear without an end tag.

<!ELEMENT PARAM - O EMPTY       -- named property value -->
  name        CDATA      #REQUIRED -- property name --
  value       CDATA      #IMPLIED  -- property value --
  valuetype (DATA|REF|OBJECT) DATA -- How to interpret value --
  type        CDATA      #IMPLIED  -- Internet media type --

In general, all attribute names and values in this specification are case insensitive, except where noted otherwise. PARAM has the following attributes:

This attribute defines the property name. The case sensitivity of the name is dependent on the code implementing the object.
This attribute is used to specify the property value. It is an opaque character string whose meaning is determined by the object based on the property name. Note that CDATA attribute values need characters such as & to be escaped using the standard SGML character entities, e.g. &amp; for "&". It is also essential to escape the > character to defend against incorrect handling by many existing browsers (use &gt;).
This attribute can be one of REF, OBJECT, or DATA as described below:
Indicates that the value is a URL. This allows support tools to identify URLs given as parameters. The value should be passed as is after dealing with any embedded character or numeric character entities, i.e. the URL should not be canonicalized before being passed to the object.
Indicates that the value is a URL of an OBJECT element in the same document. This is used primarily for object valued properties (where the value of a property is a pointer/reference to a instanciated object).
Indicates that the value is to be passed directly to the object as a string, after dealing with any embedded character or numeric character entities. This is the default in the absence of an explicit value for VALUETYPE.

Note that the VALUETYPE attribute value can be given without the corresponding attribute name, see examples below. This exploits a feature of SGML minimization.

The TYPE attribute is only valid for VALUETYPE=REF.

Example 1:

    <PARAM NAME="Caption" VALUE="Hello World!">
  is equivalent to
    <PARAM NAME="Caption" DATA VALUE="Hello World!">

The string "Hello World!" is passed to the object as the value for the "Caption" property.

Example 2:

        <OBJECT DECLARE ID=tribune

        <OBJECT CLASSID="http:// ..." DATA="KublaKhan.txt">
        <PARAM NAME=font OBJECT VALUE="#tribune">
          <P>You're missing a really cool poem viewer ...

This is a hypothetical example of an applet for viewing poems. The poem is passed to the viewer applet via the DATA attribute. The applet recognizes a parameter named "font" that defines the font as an object. The VALUE attribute uses a URL fragment identifier #tribune to point to the font object, which is itself defined with an <OBJECT DECLARE> element.

Example 3:

    <PARAM NAME="Source" REF VALUE=images/foo.gif>

The "Source" property of the object is passed the URL "images/foo.gif".

Client-Side Image Maps

Image maps allow hypertext links to be associated with shaped regions on an image. The following mechanism extends the anchor element and provides backwards compatibility with all existing browsers. It removes the need to duplicate image maps with textual hypertext menus for non-graphical browsers.

The following image is a navigation toolbar:

example toolbar

This is represented as:

    <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=rect coords="184,0,276,28">Search</a> |
        <a href=top10.html shape=rect coords="276,0,373,28">Top Ten</a>

On all HTML 2.0 browsers this would look like:

Access Guide | Go | Search | Top 10

In this case mouse clicks on the image background are processed by the server while clicks on the button "Rules of the Game" are processed locally. I think the example should be added to the draft.

The SHAPE/COORDS Attributes

If the OBJECT element includes a "SHAPES" attribute then user agents need to parse the contents of the element to look for anchors. The anchor element (<a href=...> ... </a>) is extended to permit a pair of new attributes SHAPE and COORDS. These attributes associate the hypertext link with a region on the image specified by the enclosing OBJECT element. The SHAPE/COORDS attributes take one of the general forms:


shape=rect coords="left-x, top-y, right-x, bottom-y"

shape=circle coords="center-x, center-y, radius"

shape=poly coords="x1,y1, x2,y2, x3,y3, ..."

Where x and y are measured in pixels from the left/top of the associated object. If x and y values are given with a percent sign as a suffix, the values should be interpreted as percentages of the objects' width and height, respectively. For example:

   SHAPE=RECT COORDS="0, 0, 50%, 100%"

The ISMAP attribute

When present with SHAPE and COORDS attributes, the ISMAP attribute causes the location clicked to be passed to the server. The user agent derives a new URL from the URL specified by the HREF attribute by appending `?' the x coordinate `,' and the y coordinate of the location in pixels. The link is then followed using the new URL. For instance, if the user clicked at at the location (10,27) for a link with HREF="http://www.acme.com/Guide/top10.html", then the derived URL will be: "http://www.acm e.com/Guide/top10.html?10,27".

The use of ISMAP for selected regions allows authors to exploit client-side and server-side imagemaps for the same image, e.g. regions that visually act as 3D bevelled buttons can be handled locally, while for complex image maps, or where it is undesirable to pass the imagemap to the client, the location clicked can be dealt with by the server.

An example of using SHAPE, COORDS and ISMAP:

The following image is a navigation toolbar:

Example Toolbar 2

This is represented as:

    <object data=game.gif shapes>
        <a href=guide.html shape=rect coords="0,0,118,28">Rules
              of the Game</a>
        <a href="http://www.acme.com/cgi-bin/competition"
              ismap shape=default>Guess the location</a>

In this example, mouse clicks on the toolbar background are processed by the server while clicks in the region between (0,0) and (118,28) are processed locally.

The DTD extensions for Anchors

The formal SGML definition of the ISMAP, SHAPE and COORDS attributes is:

        <!ATTLIST A
                shape   (default|rect|circle|poly)  #IMPLIED
                coords   CDATA   #IMPLIED
                ismap   (ismap)  #IMPLIED

The visually impaired community have argued strongly in favor of the shaped anchor mechanism, as it forces authors to provide a way for readers to follow the links regardless of which browser they are using.

Defining Overlapping Regions

In the following graphic, the blue and green regions are mapped to different URLs. Although the regions overlap, clicking on each region loads the appropriate document.

overlapping rectangles

If two or more regions overlap, the region defined first in the map definition takes precedence over other regions. For example, in the map definition for the graphic above, the green region is defined before the blue region:

    <object data="overlap.gif" shapes>
        <a href=green.html shape=rect coords="66,13,186,37">Green</a> |
        <a href=blue.html shape=rect coords="195,43,245,46">Blue</a>

In all cases shape=default has the lowest precedence. It extends to the whole of the visible region of the object.

Anchors can use the SHAPE attribute together with the TARGET attribute for designating the target user interface object (e.g. frame) for displaying the linked document or resource.

The MAP element

The MAP element provides an alternative mechanism for client-side image maps. It was developed by Spyglass for use with the IMG element [Ref 2]. The SHAPE and COORDS attributes are the same as for the shaped anchor mechanism. The earlier example for the toolbar becomes:

    <object data="navbar1.gif" usemap="#map1">

    <map name="map1">
        <area href=guide.html alt="Access Guide" shape=rect coords="0,0,118,28">
        <area href=search.html alt="Search" shape=rect coords="184,0,276,28">
        <area href=shortcut.html alt="Go" shape=rect coords="118,0,184,28">
        <area href=top10.html alt="Top Ten" shape=rect coords="276,0,373,28">

The OBJECT element references the MAP with a URL given with the USEMAP attribute. The SHAPE/COORDS attribute behave in the same way as for the shaped anchor proposal. The ALT attribute can be used to provide a few words describing each choice. This can't include markup, but can include character entities. Note that MAP isn't backwards compatible with HTML 2.0 browsers.


1. Hypertext link Relationships in HTML
The proposed relationships for use with REL/REV attributes are described in the Internet Draft: http://www.w3.org/pub/WWW/MarkUp/draft-ietf-html-relrev-00.txt
2. Client-Side Image maps
Spyglass Client Side Image Maps: http://www.spyglass.com/techspec/img_maps.html
3. Internet Media Types - RFC 1590
J. Postel. "Media Type Registration Procedure." RFC 1590, USC/ISI, March 1994. This can be found at ftp://ds.internic.net/rfc/rfc1590.tx t.
4. The data: URL scheme
The data: URL scheme for inline data is defined by the Internet Draft ftp://ds.internic.net/internet-drafts/draft-masinter-url-data-02.txt.
5. Java Applets
Complete specifications on Java can be found at http://java.sun.com/.
6. The clsid: URL Scheme
This is defined in http://www.w3.org/pub/WWW/Addressing/clsid-scheme.

W3C: The World Wide Web Consortium: http://www.w3.org/

Copyright  ©  1997 W3C (MIT, INRIA, Keio ), All Rights Reserved. W3C liability, trademark, document use and software licensing rules apply.