There are several methods and techniques that come handy in the case you need to call an external resource periodically or if you are waiting for a server push, but I present here an easy and straightforward one using HTML5's Server-Sent Events (SSE).
This is a reference to be used for Model rule validation and is compiled from the Yii documentation and code. The purpose is to have all the information gathered in one place instead of scattered. This reference is not an intro.
See The Definitive Guide to Yii, Declaring Validation Rules for a tutorial.
There are cases that you want more control to your menu
Suppose you want a specific menu with complex css, layout, images.