This is a three state checkbox input widget for Yii.

How to use:

1. Copy to extensions or widgets, as you wish. Then import it either manually or by adding to main.php config file imports.

   Yii::import('ext.yii-tri-state-checkbox.*');

2. Call it in your views by providing model and attribute:

   widget('CbTriStateCheckbox', array('model'=>$model,'attribute'=>'field_name')); ?>

Credits:

Inspired in this blog post: https://giweb.wordpress.com/2009/12/01/three-state-tri-state-checkboxes-in-html/