Editing Applet

{{short description|Small software application}}
{{About|small computer apps|the candy|Aplets & Cotlets|the graphing calculator applications|HP 38G|the 17th century ship|Äpplet}}
{{Original research|article|date=June 2009}}
In [[computing]], an '''applet''' is any small [[application (computing)|application]] that performs one specific task that runs within the scope of a dedicated [[widget engine]] or a larger [[program (computing)|program]], often as a [[plug-in (computing)|plug-in]].<ref>[https://web.archive.org/web/20060220131851/http://www.askoxford.com/concise_oed/applet?view=uk "AskOxford: applet"], Oxford Dictionaries. Accessed on July 21, 2009</ref> The term is frequently used to refer to a [[Java applet]], a program written in the [[Java (programming language)|Java]] programming language that is designed to be placed on a [[web page]].  Applets are typical examples of [[Application posture|transient and auxiliary applications]] that do not monopolize the user's attention. Applets are not full-featured application programs, and are intended to be easily accessible.

==History==
The word ''applet'' was first used in 1990 in ''[[PC Magazine]]''.<ref name="Origin">{{cite web
|url=http://www.oed.com
|title=Oxford English Dictionary
|year=2011
|access-date=2011-08-23
}}</ref> However, the concept of an applet, or more broadly a small interpreted program downloaded and executed by the user, dates at least to RFC 5 (1969) by [[Jeff Rulifson]], which described the [[Decode-Encode Language]], which was designed to allow remote use of the [[NLS (computer system)|oN-Line System]] over [[ARPANET]], by downloading small programs to enhance the interaction.<ref>{{citation |title= DEL |first= Jeff |last= Rulifson |work= RFC 5 |date= June 2, 1969 |publisher= Network Working Group }}</ref> This has been specifically credited as a forerunner of Java's downloadable programs in RFC 2555.<ref>{{citation |title= 30 Years of RFCs |author= ((RFC editor, et al.)) |work= RFC 2555 |date= April 7, 1999 |publisher= Network Working Group }}</ref>

==Applet as an extension of other software==
In some cases, an applet does not run independently. These applets must run either in a [[Container (data structure)|container]] provided by a host program, through a [[Plug-in (computing)|plugin]], or a variety of other applications including mobile devices that support the applet programming model.

===Web-based applets===
Applets were used to provide interactive features to web applications that historically could not be provided by [[HTML]] alone. They could capture [[Mouse (computing)|mouse input]] and also had controls like [[Button (computing)|buttons]] or [[check box]]es. In response to the user action, an applet could change the provided graphic content. This made applets well suited for demonstration, visualization, and teaching. There were online applet collections for studying various subjects, from physics to heart physiology. Applets were also used to create online game collections that allowed players to compete against live opponents in real-time.

An applet could also be a text area only, providing, for instance, a cross-platform [[command-line interface]] to some remote system. If needed, an applet could leave the dedicated area and run as a separate [[Window (computing)|window]]. However, applets had very little control over web page content outside the applet dedicated area, so they were less useful for improving the site appearance in general (while applets like [[news ticker]]s or [[WYSIWYG]] editors are also known). Applets could also play media in formats that are not natively supported by the browser.

HTML pages could embed parameters that were passed to the applet. Hence, the same applet could appear differently depending on the parameters that were passed.

Examples of Web-based applets include:{{citation needed|date=August 2012}}

* [[QuickTime|QuickTime movies]]
* [[SWF|Flash movies]]
* [[Windows Media Player]] applets, used to display embedded video files in [[Internet Explorer]] (and other [[Web browser|browsers]] that supported the plugin)
* [[3D modeling]] display applets, used to rotate and zoom a model
* [[Browser game]]s that were applet-based, though some developed into fully functional applications that required installation.

===Applet Vs. Subroutine===
A larger application distinguishes its applets through several features:{{Citation needed|date=July 2009}}

* Applets execute only on the "client" platform environment of a system, as contrasted from "[[Java Servlet|Servlet]]". As such, an applet provides functionality or performance beyond the default capabilities of its container (the browser).
* The container restricts applets' capabilities.
* Applets are written in a language different from the scripting or HTML language that invokes it. The applet is written in a compiled language, whereas the scripting language of the container is an interpreted language, hence the greater performance or functionality of the applet. Unlike a subroutine, a complete web component can be implemented as an applet.

==Java applets==
{{Main|Java applet}}

A Java applet is a Java program that is launched from HTML and run in a web browser. It takes code from server and run in a web browser. It can provide web applications with interactive features that cannot be provided by HTML. Since Java's [[bytecode]] is platform-independent, Java applets can be executed by browsers running under many platforms, including [[Microsoft Windows|Windows]], [[Unix]], [[macOS]], and [[Linux]]. When a Java technology-enabled web browser processes a page that contains an applet, the applet's [[code]] is transferred to the client's system and executed by the browser's [[Java virtual machine]].<ref>{{Cite web |date=October 5, 2023 |title=Applets |url=https://www.oracle.com/java/technologies/applets.html |access-date=October 5, 2023 |website=oracle.com}}</ref> An HTML page references an applet either via the [[Deprecation|deprecated]] [[HTML element#applet|{{tag|applet|o}} tag]] or via its replacement, the [[HTML element#object|{{tag|object|o}} tag]].<ref>[https://www.w3schools.com/TAGS/tag_applet.asp "HTML applet tag"], W3Schools. Access on July 21, 2009
</ref>

==Security==
Recent developments in the coding of applications, including mobile and [[embedded system]]s, have led to the awareness of the security of applets.

===Open platform applets===
Applets in an [[open platform]] environment should provide secure interactions between different applications. A compositional approach can be used to provide security for open platform applets.<ref name="Compositional">{{cite book
|chapter=Compositional Verification of Secure Applet Interactions
|last1=Barthe
|first1=Gilles
|title=Fundamental Approaches to Software Engineering
|volume=2306
|pages=15–32
|last2=Gurov
|first2=Dilian
|last3=Huisman
|first3=Marieke
|year=2002
|citeseerx=10.1.1.16.1254
|doi=10.1007/3-540-45923-5_2
|series=Lecture Notes in Computer Science
|isbn=978-3-540-43353-8
}}</ref>  Advanced compositional verification methods have been developed for secure applet interactions.<ref name="Compositional"/>

===Java applets===
A [[Java applet]] contains different security models: [[Java applet#Unsigned|unsigned Java applet security]], [[Java applet#Signed|signed Java applet security]], and [[Java applet#Self-signed|self-signed Java applet security]].

===Web-based applets===
In an applet-enabled web browser, many methods can be used to provide applet security for malicious applets. A malicious applet can infect a computer system in many ways, including denial of service, invasion of privacy, and annoyance.<ref name="Controlling">{{cite book
|chapter=Controlling Applets' Behavior in a Browser
|last1=Hassler
|first1=Vesna
|title=Proceedings 14th Annual Computer Security Applications Conference (Cat. No.98EX217)
|pages=120–125
|last2=Then
|first2=Oliver
|year=1998
|doi=10.1109/CSAC.1998.738594
|isbn=978-0-8186-8789-1
|s2cid=17633591
}}</ref>  A typical solution for malicious applets is to make the web browser to monitor applets' activities. This will result in a web browser that will enable the manual or automatic stopping of malicious applets.<ref name="Controlling"/>

==See also==
{{Portal|Computer programming}} 
* [[Application posture]]
* [[Bookmarklet]]
* [[Java applet]]
* [[Widget engine]]
* [[Abstract Window Toolkit]]

==References==
{{Reflist|30em}}

==External links==
{{Wiktionary|applet}}

[[Category:Technology neologisms]]
[[Category:Component-based software engineering]]
[[Category:Java (programming language) libraries]]