• Applet ia a java program that runs in a web browser .
• Applet is a java class that extends the java.applet.Applet class.
• no main() method
• Applet are designed to be embedded witnin an Html page
• JVM is required to view an applet .
• Applet have strict security rules that are enforced by the web browser.

• These applet use the abstract window toolkit(AWT) to provide the graphical user interface.
• This style of applet has been availble since java was first created.

• are based on the swing class JApplet , which inherits Applet.
• swing applets use the swing classes to provide the GUI.

When an applet begins, the following methods are called in this sequence:

1. init() :

   init() is the 1st method to be called. this is where variables are initialized. this method is only called ine time of an applet.

2. start() :

   start() is called after init method . It is called to re-start an applet after it has been stopped. start() is called each time an applets document is displayed in screen so if a user leaves a web page and comes back the applet resumes execution at start().

3. paint() :

   paint() is called each time an AWT based applets output must be redrawn. This situation can occur for several reason. Whenever the applet must redraw its output paint() is called. The paint() has one parameter of type Graphics.

When an applet is terminated the following sequence of method calls take place:

1. Stop() :

   Stop() is called when a web browser.You should use Stop() to suspend threats that dont need to run when the applet is not visible

2. Destroy() :

   The Destroy() is called when the environment determines that your applets needs to be removed completely from memory. At this point you should free up any resources the applet may be using. The Stop() is always called before Destroy().

Syntax:

```
<Applet
[CODEBASE = codebaseURL]
CODE = appletFile
[ALT = alternateText]
[NAME = appletInstanceName]
Width = pixels
height = pixels
[ALIGN = alignment]
[VSPACE = pixels]
[HSPACE = pixels]
>

[< PARAM NAME = attributeName VALUE = AttributeValue>] 
[HTML Displayed in the absence of Java]

</APPLET>
```
*Note : [] -> Optional 

• It is an optional attribute that specifies the base URL of the applet code, which is the directory that will be searched for the applets executable class file.
• The HTML Document URL Directory is used as the CODEBASE if this attribute is not specified.

• Code is the required attribute that gives the name of file containing compiled .class file. This file is related to the code base UTL of the applet.

• The ALT tag is an alternate tag used to specify a short text message that should be displayed if the browser recognized the applet tag but can't currently run JAVA applet.

• NAME is an optional attribute used to specify a name for the applet instance. NAME attribute is used in order to communicate between applets on the same page.

• WIDTH and HEIGHT are the required attributes that gives the size of the applet display area.

• ALIGN is an optional attribute that specifies the alignment of the applet. The possible values are Left, Right, Top, Bottom, Middle, Baseline, Texttop, Absmiddle (Absolute Middle) and Absbottom .

• These attributes are optinal.
• VSPACE specifies the space in pixel and below the applet.
• HSPACE specifies the space in pixel on each sides of the applet.

• PARAM tag allows you to specify applet specific arguments.
• Applets access their attributes with the getParameter( )