Many internet browsers allocate a thread for each applet on a page, using that thread for all calls to the applet's major methods.
Some browsers allocate multiple threads or a thread group for each applet.
Multiple threads share more of their enrivonment with each other than singletasking. Threads may be distinguished by the value of their program counters and stack address while sharing a multiple address space and set of variables. The threads that the major methods are called from depends on the application that is running the applet, so that it is easy to kill or get the control part or all the threads that belong to a particular applet. It is difficult to directly discover the flaws in the design and implementation of internet browsers.