Applets are programs that can be downloaded from a foreign machine through a network and executed on a local machine.
Applets are not controlled by local operating system
Applets are split into small packets called bytecode and travel across the network . These bytecodes are reassembled at receiving machine of the network by the JVM and executed by the browser. Applets can not be executed directly. An applet can only be the element of the HTML page. There for applet can only be executed by executing HTML page.