Yes, applets were already interactive and programmable. But they sort of ran "in a box", like Flash. So you have this particular rectangle in the page, inside

Yes, applets were already interactive and programmable. But they sort of ran "in a box", like Flash. So you have this particular rectangle in the page, inside of it something runs and works and does its thing... but outside of it, the rest of the page knows nothing of that. What JavaScript was supposed to bring into the mix was that you might have a Java applet doing some "heavy-lift" stuff and then, you'd use the results of that to operate on other elements in the page. Like maybe you'd update a form, or some data in the HTML, or whatever. Also, obviously, the other way around. You might have some HTML controls that would then feed user data into the applet. Yes, you could do everything inside the applet, but this offered an additional option.