We really need to implement the missing functionality Java applets are providing in plain JS, so applets can die. The last time i absolutely had to implement an applet was to provide my client with this functionality that was not available with pure JS:

- direct access to printer: the user wanted to print on a specific tray of the printer, without selecting it every time. JS only implements window.print() with no fine grained printer control.

- serial/parallel/usb access: access to a POS for card processing, and we needed to write some data on a smartcard.

- plain TCP connections

- read/write files on the local filesystem.

I understand that all these features require more control of the underlying hardware and need to be somehow secured, but we did not want to write a desktop app just for these features, and applets gave us the means to implement what the user needed. Once JS can do that, applets can die a quick dead.