APPLET - Java Applet



Attribute Specifications

[3.2] ALT=Text (alternate text)
[3.2] CODE=CDATA (class file)
[3.2] CODEBASE=url (base url for class files)
[3.2] WIDTH=Length (applet width)
[3.2] HEIGHT=Length (applet height)
[3.2] HSPACE=Pixels (horizontal gutter)
[3.2] VSPACE=Pixels (vertical gutter)
[3.2] NAME=CDATA (name for inter-applet communication)
[Netscape] [3.2] ALIGN=[ top | middle | bottom | left | right ] (applet alignment)
[Netscape] ARCHIVE=CDATA (archive files)
[Netscape] MAYSCRIPT
[4.0] OBJECT=CDATA (serialized applet)
[4.0] ID=string
[4.0] CLASS=string
[4.0] STYLE=string
[4.0] TITLE=string
[4.0] LANG=Language (i.e. RU - Russian)
[4.0] DIR=ltr|rtl

Can Contain:

PARAM elements followed by block-level elements and/or inline elements

Contained in:

Inline elements, block-level elements except PRE


The APPLET element is used to embed Java applets. It has been deprecated in HTML 4.0 in favor of the more generalized OBJECT element. However, since the few browsers that support OBJECT do so with significant bugs, APPLET is currently a more reliable method of embedding Java applets.

An APPLET may contain PARAM elements to define applet-specific parameters. PARAM elements should be specified before any other content of the APPLET element. In the following example, a decorative Java applet takes two parameters. The APPLET contains an animated GIF as an alternative for non-Java browsers.

<APPLET CODE="Animate.class" WIDTH=100 HEIGHT=100>
<PARAM NAME=img1 VALUE="/images/1.jpg">
<PARAM NAME=img2 VALUE="/images/2.jpg">
<IMG SRC="animation.gif" ALT="" WIDTH=100 HEIGHT=100>

[3.2] ALT

The ALT attribute can be used to give alternate text for browsers that recognize the APPLET element but do not support Java or do not have Java enabled. Authors can also give alternate content between the start and end tags of the APPLET element--a better method than using the ALT attribute since it allows authors to include HTML markup in the alternate content and also works with pre-HTML 3.2 browsers that do not support APPLET.


APPLET's CODE attribute specifies the name of the class file that contains the compiled Applet subclass. The value is relative to the url specified in the CODEBASE attribute, or to the HTML document's base url if the CODEBASE attribute is not given.

<APPLET CODE="Animate.class" WIDTH=100 HEIGHT=100>
<PARAM NAME=img1 VALUE="/images/1.jpg">
<PARAM NAME=img2 VALUE="/images/2.jpg">
<IMG SRC="animation.gif" ALT="" WIDTH=100 HEIGHT=100>


The required WIDTH and HEIGHT attributes define the dimensions of the applet. The value may be given in pixels or as a percentage of the parent element's width or height.


The HSPACE and VSPACE attributes allow an author to suggest horizontal gutters and vertical gutters, respectively, around the applet. The value must be in pixels and applies to both sides of the applet. Style sheets provide more flexibility in specifying the space around applets.

[3.2] NAME

"This attribute specifies a name for the applet instance, which makes it possible for applets on the same page to find (and communicate with) each other." (W3C)

[Netscape] ARCHIVE

The ARCHIVE attribute can specify a comma-separated list of archived files (either absolute urls or urls relative to the CODEBASE), allowing the browser to download many files with a single connection and hence decreasing the total download time. The standard archive format for Java files is JAR. JAR files can be created with the jar tool included with the Java Development Kit 1.1 and up.

Note that some browsers do not support the ARCHIVE attribute, so all necessary files should be available unarchived as well. Other browsers only support a single url as the ARCHIVE value.

[Netscape] MAYSCRIPT

"...permits the applet to access JavaScript. Use this attribute to determine whether or not an applet can access JavaScript on a page without your knowledge. Accessing JavaScript when the MAYSCRIPT attribute is not specified results in an exception." (Netscape 4.0)

[3.2] [Netscape] ALIGN

The ALIGN attribute specifies the alignment of the applet. The values top, middle, and bottom specify the applet's position with respect to surrounding content on its left and right.

ALIGN=middle aligns the center of the applet with the current baseline. To center the applet horizontally on the page, place the applet in a centered block, e.g.,

<P ALIGN=center><APPLET CODE="Game.class" WIDTH=300 HEIGHT=100></APPLET></P>

The other ALIGN values, left and right, specify a floating applet; the applet is placed at the left or right margin and content flows around it. To place content below the applet, use <BR CLEAR=left|right|all> as appropriate.

The vertical-align and float properties of Cascading Style Sheets provide more flexible methods of aligning applets.


"Indicates the order of image download" Web TV 1.2 DTD.
It seems doubtful whether this attribute works under IE and Netscape.


The OBJECT attribute specifies a serialized (saved) representation of an applet. The CODE attribute should not be used if and only if the OBJECT attribute is specified. When the applet is deserialized, its init() method is not invoked, but its start() method is. Sun recommends restraint in using this poorly supported feature.

[4.0] ID

The ID attribute uniquely identifies an element within a document. No two elements can have the same ID value in a single document. The attribute's value must begin with a letter in the range A-Z or a-z and may be followed by letters (A-Za-z), digits (0-9), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").

The following example uses the ID attribute to identify each of the first two paragraphs of a document:

<P ID=firstp>My first paragraph.</P>
<P ID=secondp>My second paragaph.</P>

The paragraphs in the example could have style rules associated with them through their ID attributes. The following Cascading Style Sheet defines unique colors for the two paragraphs:

P#firstp {
  color: navy;
  background: transparent

P#secondp {
  color: black;
  background: transparent

The paragraphs in the initial example could also be used as a target anchor for links:

<P>See <A HREF="#firstp">the opening paragraph</A> for more information.</P>

Note that most browsers do not support the ID attribute for link anchors. For current browsers, authors should use <A NAME>...</A> within the element instead of ID.

Since ID and NAME share the same name space, authors cannot use the same value for an ID attribute and a NAME attribute in the same document. Also note that while NAME may contain entities, the ID attribute value may not.

[4.0] CLASS

The CLASS attribute specifies the element to be a member of one or more classes. Classes allow authors to define specific kinds of a given element. For example, an author could use <CODE CLASS=Java> when giving Java code and <CODE CLASS=Perl> when giving Perl code.

Unlike with the ID attribute, any number of elements can share the same class. An element may also belong to multiple classes; the CLASS attribute value is a space-separated list of class names.

Note that most current browsers do not support multiple classes. Such browsers typically ignore a CLASS attribute that specifies multiple classes.

The CLASS attribute is particularly useful when combined with style sheets. For example, consider the following navigation bar:

<DIV CLASS=navbar>
<P><A HREF="/">Home</A> | <A HREF="./">Index</A> | <A HREF="/search.html">Search</A></P>
<P><A HREF="/"><IMG SRC="logo.gif" ALT="" TITLE="WDG Logo"></A></P>

This example's use of the CLASS attribute allows style rules to easily be added. The following Cascading Style Sheet suggests a presentation for the preceding example:

.navbar {
  margin-top: 2em;
  padding-top: 1em;
  border-top: solid thin navy

.navbar IMG { float: right }

@media print {
  .navbar { display: none }
[4.0] STYLE

The STYLE attribute allows authors to specify style rules inline for a single occurrence of an element. An example follows:

<P>A popular font for on-screen reading is <SPAN STYLE="font-family: Verdana">Verdana</SPAN>.</P>

When the STYLE attribute is used, a default style sheet language must be specified for the document by setting the Content-Style-Type HTTP header to the media type of the style sheet language. The previous example could use the following META element in the document's HEAD:

<META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css">

In most cases, use of the CLASS or ID attributes is a better choice than using STYLE since ID and CLASS can be selectively applied to different media and since they provide a separation of content and presentation that often simplifies maintenance.

[4.0] TITLE

The TITLE attribute provides a title for an element and is commonly implemented as a "tooltip" on visual browsers, though many browsers lack support for TITLE. The attribute is most useful with A, LINK, IMG, and OBJECT elements, where it provides a title for the linked or embedded resource. Some examples follow:

TITLE is also helpful with the ABBR and ACRONYM elements to provide the long form of the abbreviation. Examples:

Internationalization Attributes

[4.0] LANG

The LANG attribute specifies the language of an element's attribute values and its content, including all contained elements that do not specify their own LANG attribute. While the LANG attribute is not widely supported, its use may help search engines index a document by its language while allowing speech synthesizers to use language-dependent pronunciation rules. As well, visual browsers can use the language's proper quotation marks when rendering the Q element.

The attribute value is case-insensitive, and should be specified according to RFC 1766; examples include en for English, en-US for American English, and ja for Japanese. Whitespace is not allowed in the language code.

Use of the LANG attribute also allows authors to easily change the style of text depending on the language. For example, a bilingual document may have one language in italics if rendered visually or a different voice if rendered aurally. The HTML of such a document might be as follows:

<TITLE>Welcome - Bienvenue</TITLE>
  <SPAN LANG=en>Welcome</SPAN> -
  <SPAN LANG=fr>Bienvenue</SPAN>
<P LANG=en>This paragraph is in English.</P>
<P LANG=fr>Ce paragraphe est en français.</P>

A document's primary language may be set using the LANG attribute on the HTML element, or, alternatively, by using the Content-Language HTTP header.

[4.0] DIR

The DIR attribute specifies the directionality of text--left-to-right (DIR=ltr, the default) or right-to-left (DIR=rtl). Characters in Unicode are assigned a directionality, left-to-right or right-to-left, to allow the text to be rendered properly. For example, while English characters are presented left-to-right, Hebrew characters are presented right-to-left.

Unicode defines a bidirectional algorithm that must be applied whenever a document contains right-to-left characters. While this algorithm usually gives the proper presentation, some situations leave directionally neutral text and require the DIR attribute to specify the base directionality.

Text is often directionally neutral when there are multiple embeddings of content with a different directionality. For example, an English sentence that contains a Hebrew phrase that contains an English quotation would require the DIR attribute to define the directionality of the Hebrew phrase. The Hebrew phrase, including the English quotation, should be contained within a SPAN element with DIR=rtl.

[4.0] Scripting Events

A number of attributes that define client-side scripting events are common to most elements. The attribute value is a script--typically a function call or a few short statements--that is executed when the event occurs. The value may contain entities (e.g., &quot;).

The following example features JavaScript code to handle two events of a submit button, giving the user a reminder in the status bar when the mouse moves over the button and clearing the status bar when the mouse moves away. Note that the attribute values are delimited by single quotes since double quotes are used within them.

<INPUT TYPE=submit ONMOUSEOVER='window.status="Did you fill in all required fields?";' ONMOUSEOUT='window.status="";'>

When an event attribute is used, a default scripting language must be specified for the document by setting the Content-Script-Type HTTP header to the media type of the scripting language. The previous example could use the following META element in the document's HEAD:

<META HTTP-EQUIV="Content-Script-Type" CONTENT="text/javascript">

The common event attributes are device-dependent and largely tailored for the graphical user interface. The available events are as follows:

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