Components are the main building blocks of Yii applications. Components are instances of yii\base\Component, or an extended class. The three main features that components provide to other classes are:
Separately and combined, these features make Yii classes much more customizable and easier to use. For example, the included date picker widget, a user interface component, can be used in a view to generate an interactive date picker:
use yii\jui\DatePicker; echo DatePicker::widget([ 'language' => 'ru',