Protocol which allows a web client and a web server to dialogue. Script language executed on the server enabling data to be handled before sending it to the client computer. It is generally a CGI script which manages the data from forms which you can send from a web page. Javascript Script language integrated in a HTML page which your browser executes when it reads and posts up the HTML page.
Javascript language is relatively simple but weak.
Java Applet Program sent by the server, which is executed due to a Java interpreter integrated into your browser. A Java applet can carry out extremely powerful operations. Programming in Java language is all the more complex. The browser reads the HTML page, interprets the markers and links and posts it on your screen. You can probably see the HTML page source from a drop down menu on your browser.