This chapter explains what you need to know about HTML
to work with Java applets.
A Java applet is included in a Web page with the
<APPLET> tag, which has the following syntax. Items
in brackets ([]) are optional.
<APPLET
CODE = applet-filename
WIDTH = pixel-width
HEIGHT = pixel-height
[OBJECT = serialized-applet-filename]
[ARCHIVE = jar-file-list]
[CODEBASE = applet-url]
[ALT = alternate-text]
[NAME = applet-name]
[ALIGN = alignment]
[VSPACE = vertical-pixel-space]
[HSPACE = horizontal-pixel-space]
>
[<PARAM NAME = parameter VALUE = value>]
[<PARAM NAME = parameter VALUE = value>]
...
[alternate-text]
</APPLET>
- APPLET
-
The <APPLET> tag specifies an applet to be run
within a Web document. A Web browser that does not support Java
and does not understand the <APPLET> tag ignores
this tag and any related <PARAM> tags, and simply
displays any alternate-text that appears between
<APPLET> and </APPLET>. A browser that does
support Java runs the specified applet, and does
not display the alternate-text.
- CODE
-
This required attribute specifies the file that contains the
compiled Java code for the applet. It must be relative to
the CODEBASE if that attribute is specified, or
relative to the current document's URL. It must not be an
absolute URL. In Java 1.1, this attribute can be replaced
with an OBJECT attribute.
- WIDTH
-
This attribute specifies the initial width, in pixels, that
the applet needs in the browser's window. It is required.
- HEIGHT
-
This attribute specifies the initial height, in pixels, that
the applet needs in the browser's window. It is required.
- OBJECT
-
As of Java 1.1, this attribute specifies the name of
a file that contains a serialized applet that is to be
created by deserialization. An applet specified in this way
does not have its init() method invoked, but does have
its start() method invoked. Thus, before an
applet is saved through serialization, it should be
initialized, but should not be started, or, if started, it
should be stopped. An applet must have either the
CODE or OBJECT attribute specified, but not
both.
- ARCHIVE
-
As of Java 1.1, this attribute specifies a
comma-separate list of JAR (Java Archive) files that are
"preloaded" by the Web browser or applet viewer. These
archive files may contain Java class files, images, sounds,
properties, or any other resources required by the applet.
The Web browser or applet viewer searches for required
files in the archives before attempting to load them over
the network.
- CODEBASE
-
This optional attribute specifies the base URL (absolute or
relative) of the applet to be displayed. This should be a
directory, not the applet file itself. If this attribute is
unspecified, then the URL of the current document is used.
- ALT
-
This optional attribute specifies text that should be
displayed by browsers that understand the <APPLET>
tag but do not support Java.
- NAME
-
This optional attribute gives a name to the applet instance.
Applets that are running at the same time can look each
other up by name and communicate with each other.
- ALIGN
-
This optional attribute specifies the applet's alignment on
the page. It behaves just like the ALIGN attribute
of the <IMG> tag. Its allowed values are:
left, right, top, texttop,
middle, absmiddle, baseline,
bottom, and absbottom.
- VSPACE
-
This optional attribute specifies the margin, in pixels,
that the browser should put above and below the applet. It
behaves just like the VSPACE attribute of the
<IMG> tag.
- HSPACE
-
This optional attribute specifies the margin, in pixels,
that the browser should put on either side of the applet.
It behaves just like the HSPACE attribute of the
<IMG> tag.
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