A client side server is / the client part of a server are calculations / processing which is done on your (ie. the end-user's) PC. Java-script is a client-side scripting language as it runs on your computer. Perl is a server-side language because the server processes it. In terms of games, there is often talk of trying to do as much client side work as possible, as this means less data has to be transferred around by the server. The less data the server has to transmit, the faster and less laggy the game will be.
ActiveX controls. Applications such as Internet Explorer have components, such as the actual area which displays the web page, which Microsoft wants to share between several applications. So an ActiveX control is created, which is a .OCX file, a bit like a library, which can be used by any program. ActiveX controls can also be inserted into a webpage, using the <OBJECT> tag. Flash animations, Internet Explorer are examples of ActiveX controls.
