All applets are extended from a class called java.applet.Applet and has the following methods:
init()initializes the applet
start()starts the applet
stop()stops the applet
destroy()cleans up resources when applet is finished
getAudioClip(URL url)retrieves an audio clip
getAudioClip(URL url, String name)overloaded method that allows the specification of the name of the audio clip
getCodeBase()returns URL where the applet resides
getDocumentBase()returns URL of HTML page where applet is embedded
getImage(URL url)retrieves image
getImage(URL url, String name)retrieves named image
getParameter(String name)returns a parameter from HTML page
getParameterInfo()returns an array of strings that enables you to retrieve more than one parameter to the applet
isActive()returns Boolean identifying whether applet is active
play(URL url)plays an audio clip
play(URL url, String name)plays a named audio clip
resize(int width, int height)resizes the applet
resize(Dimension d)resizes the applet
showStatus(String msg)prints message on the appletviewer's status bar or a browser's panel

Here's the complete syntax for the APPLET tag:

'<' 'APPLET'
['CODEBASE' '=' codebaseURL]
'CODE' '=' appletFile
['ALT' '=' alternateText]
['NAME' '=' appletInstanceName]
'WIDTH' '=' pixels 'HEIGHT' '=' pixels
['ALIGN' '=' alignment]
['VSPACE' '=' pixels] ['HSPACE' '=' pixels]
['<' 'PARAM' 'NAME' '=' appletAttribute1 'VALUE' '=' value '>']
['<' 'PARAM' 'NAME' '=' appletAttribute2 'VALUE' '=' value '>']
. . .

'CODEBASE' '=' codebaseURL
This optional attribute specifies the base URL of the applet -- the directory that contains the applet's code. If this attribute is not specified, then the document's URL is used.

'CODE' '=' appletFile
This required attribute gives the name of the file that contains the applet's compiled Applet subclass. This file is relative to the base URL of the applet. It cannot be absolute.

'ALT' '=' alternateText
This optional attribute specifies any text that should be displayed if the browser understands the APPLET tag but can't run Java applets.

'NAME' '=' appletInstanceName
This optional 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.

'WIDTH' '=' pixels 'HEIGHT' '=' pixels
These required attributes give the initial width and height (in pixels) of the applet display area, not counting any windows or dialogs that the applet brings up.

'ALIGN' '=' alignment
This required attribute specifies the alignment of the applet. The possible values of this attribute are the same as those for the IMG tag: left, right, top, texttop, middle, absmiddle, baseline, bottom, absbottom.

'VSPACE' '=' pixels 'HSPACE' '=' pixels
These option attributes specify the number of pixels above and below the applet (VSPACE) and on each side of the applet (HSPACE). They're treated the same way as the IMG tag's VSPACE and HSPACE attributes.

'<' 'PARAM' 'NAME' '=' appletAttribute1 'VALUE' '=' value '>' . . .
This tag is the only way to specify an applet-specific attribute. Applets access their attributes with the getParameter() method.

<APPLET CODE = ImageLoopItem
width = 80
height = 90>
<PARAM NAME=pause VALUE=1000>