A behavior can be used to enhance the functionality of an existing component without modifying its code. In particular, it can "inject" its own methods and properties into the component and make them directly accessible via the component. It can also respond to the events triggered in the component and thus intercept the normal code execution.
行為（Behaviors）
在Yii框架中，行為實現(xiàn)了Mixin模式碉怔。它們可以增強(qiáng)組件的功能，但是不用修改組件的代碼怀读； 行為還可以響應(yīng)在組件中觸發(fā)的事件箕憾，從而攔截正常代碼的執(zhí)行。與PHPTraits不同，behaviors可以在代碼運(yùn)行時颓哮，附加到類。
