Nowadays most web pages contain something dynamic or moving. The technology responsible for this (scripts) can be classified by whether the action takes place on the client computer or on the server computer.
Microsoft has an own version: JScript.
The Microsoft competitor to Java applets. May be written in many programming languages, mostly however in Visual Basic. Uses however special Windows features, therefore doesn't mix well with other operating systems. Since ActiveX programs have more rights on your computer than Java applets and can do almost everything, some people consider them to be potentially more dangerous than Java applets.
Be sure to choose the settings (Tools-Internet Options-Security for Internet Explorer---there you distinguish between four site categories) balancing safety and freedom best
In the above case of applets on the browser side, the server has no idea how the browser interacts with the programs the server provided. If the browser is expected to respond some information to the server, programs have to run on the server. See a CPT106 page for more information on server-side scripts.