By the end of this tutorial, you’ll understand legacy Java applet markup and what to use instead in modern web development.
How <applet> embedded Java programs with code, width, and height.
Understand codebase, archive, alt, and <param> configuration.
Games, charts, animations, and interactive demos before JavaScript matured.
Why HTML5 removed <applet> and discontinued the Java Plugin.
Replace applets with JavaScript, Canvas, WebGL, CSS, and WebAssembly.
Know when you’ll encounter applet in old codebases and how to migrate away.
<applet> Tag?The applet element (<applet>) was used to embed a Java applet—a compiled Java program (.class file) that executed inside the browser via the Java Plugin. Applets enabled interactive animations, games, charts, and calculators before JavaScript matured.
The <applet> tag is removed from the HTML5 specification and no longer supported by modern browsers. Java applets required a browser plugin that has been discontinued. Do not use this tag in any new project.
As of HTML5, the tag is obsolete. Browsers have removed Java Plugin support due to security vulnerabilities and the availability of safer, native web technologies like JavaScript and HTML5 Canvas.
The syntax involved specifying attributes like code, width, and height to define the applet’s properties, with fallback content inside the tag:
<!-- Legacy Java applet syntax -->
<applet code="YourAppletClass.class" width="300" height="200">
<!-- Alternative content if the applet cannot be displayed -->
Your browser does not support the <code><applet></code> tag.
</applet>code points to the compiled Java .class file to execute.width and height set the display area in pixels.<param> child elements pass name/value pairs to the Java program.| Attribute | Code Snippet | Purpose |
|---|---|---|
code | code="MyApplet.class" | Path to the compiled Java class file |
width / height | width="300" height="200" | Dimensions of the applet display area |
codebase | codebase="/applets" | Base directory for class files and archives |
archive | archive="app.jar" | Comma-separated list of JAR archives |
alt | alt="Java animation demo" | Short description when the applet cannot load |
<param> | <param name="speed" value="fast"> | Passes configuration values to the applet |
The <applet> tag supported several attributes for configuring the embedded Java program:
code RequiredSpecifies the applet’s compiled Java class file (e.g. MyApplet.class).
code="Animation.class"width / height RequiredDefines the width and height of the applet display area in pixels.
width="400" height="300"codebase OptionalBase URL or directory path for the applet’s class files and archives.
codebase="/applets"archive OptionalOne or more JAR files containing the applet and its dependencies.
archive="app.jar,lib.jar"alt A11yAlternative text for browsers that cannot display the applet.
alt="Java animation demo"<param> ChildChild elements that pass name/value configuration to the Java program.
<param name="color" value="blue">All applet attributes are historical only. The entire element is obsolete in HTML5.
Historical Java applet patterns with copy-ready code. Modern browsers show only the fallback content inside the tag.
The simplest historical form: specify the Java class, dimensions, and fallback content for browsers without applet support (which today means all modern browsers).
<applet code="YourAppletClass.class" width="300" height="200">
Your browser does not support the <code><applet></code> tag.
</applet>In the past, the <applet> tag was widely used for integrating Java applets into web pages—animations, data visualizations, educational demos, and games. Due to security concerns and the evolution of web technologies, Java applets have become outdated.
Developers passed configuration to applets using <param> child elements and set the class file location with codebase and archive attributes.
<applet code="Animation.class" codebase="/applets" width="400" height="300" alt="Java animation demo">
<param name="speed" value="fast">
<param name="color" value="blue">
Java applets are no longer supported in modern browsers.
</applet>The <applet> tag is deprecated and obsolete. It is no longer recommended for use in modern web development.
Security CriticalJava applets were a frequent attack vector and major security vulnerability in browsers.
Plugin dependency RemovedRequired a separate Java browser plugin, now discontinued in all major browsers.
Performance IssueSlower startup and higher memory use compared to native JavaScript and WebAssembly.
Alternatives ModernJavaScript, Canvas, WebGL, CSS animations, and WebAssembly are safer and faster.
Given the obsolete status of <applet>, use these technologies for interactive web content today:
JavaScript NativeDOM manipulation, events, and application logic without browser plugins.
document.querySelector(...)Canvas / WebGL Graphics2D drawings, games, and 3D visualizations directly in the browser.
<canvas id="game"></canvas>CSS Animations MotionTransitions and keyframe animations without Java or plugins.
@keyframes fadeIn { ... }WebAssembly WASMNear-native performance for compute-heavy browser applications.
WebAssembly.instantiate(...)If you encounter <applet> in legacy code, plan to remove or replace it. Modern web development relies on JavaScript, HTML5, and CSS for creating dynamic and interactive content. For maintaining old sites, document the applet functionality and rebuild with current web APIs.
The parser encounters <applet> and reads code, width, height, and param values.
The browser plugin downloaded and executed the .class or .jar file inside a sandboxed Java runtime.
The Java program drew graphics and handled user input within the allocated width and height.
JavaScript and HTML5 APIs deliver the same interactivity without plugins. The <applet> tag exists only in web history and legacy maintenance.
The <applet> tag has no functional support in modern browsers. All major browsers have removed Java Plugin support. The tag should be treated as non-functional in modern environments.
All major browsers have removed Java Plugin support. Modern browsers show only the fallback content inside the <applet> tag—the Java program itself will not execute.
Security, performance, and native web technology maturity drove universal deprecation.
Bottom line: Learn <applet> for legacy maintenance only. Use JavaScript, Canvas, or WebAssembly for all new interactive content.
While the <applet> tag played a significant role in early web development, its deprecated status makes it unsuitable for modern web projects.
Developers should adopt contemporary technologies—JavaScript, HTML5 Canvas, CSS, and WebAssembly—to create dynamic and engaging web content without relying on discontinued browser plugins.
<applet> tags when maintaining old sites<applet> in any new HTML5 project<applet> with <embed> or <object> for modern media<applet> tagUnderstand the history, then build with modern web-native technologies.
<applet> embedded compiled Java programs via the Java Plugin.
code, width, and height configured the embedded program.
The tag is obsolete and not valid in conforming HTML5 documents.
ObsoleteJava Plugin removed from Chrome, Firefox, Safari, Edge, and Opera.
SecurityCanvas, WebGL, CSS, and WebAssembly replace applets for interactivity.
MigrationStudy for legacy code only—never use in new HTML5 projects.
Guidance<applet> element embedded Java applets—compiled Java programs that ran inside the browser via the Java Plugin for interactive content.<applet> tag. The Java program itself will not execute.Skip obsolete applets. Practice modern HTML and JavaScript in the live editor.
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