In computing, an applet is any small application that performs one specific task that runs within the scope of a dedicated widget engine or a larger program, often as a plug-in.
Applets are typical examples of transient and auxiliary applications that do not monopolize the user's attention.
[2] 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 oN-Line System over ARPANET, by downloading small programs to enhance the interaction.
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.
[6] Recent developments in the coding of applications, including mobile and embedded systems, have led to the awareness of the security of applets.
A malicious applet can infect a computer system in many ways, including denial of service, invasion of privacy, and annoyance.