title: Yii ClientScript
body: <p>I would like to know is there a way to check if a coreScript is already registered?</p>
  
  <p>for example the yiiactiveform</p>
  
  <p><code>Yii::app()->clientScript->registerCoreScript('yiiactiveform');</code></p>
  
  <p>how to check if this corescript is already registered?
  thanks</p>