General Control

Though optional, you could have the total control of the client's functionality without the assistance of server-side code. Generally, you don't need to do it. You don't need to know how ZK Client Engine and client-side widgets communicate with the server. Their states are synchronized automatically by ZK. However, you could control it if necessary. It is the so-called Server-client fusion.

The rule of thumb is you should handle most of, if not all, events and manipulate UI at the server, since it is much more productive. Then, you could improve the responsiveness and visual effects, and/or reduce the load of the server by handling them at the client, when it is appropriate. Notice that JavaScript is readable by any user, so be careful not to expose sensitive data or business logic when migrating some code from server to client.

In this chapter, we will discuss the details of the client-side control and programming.