Yii's CJuiDatePicker doesn't work for me

I copied the Yii documentation's example for CJuiDatePicker:

$this->widget('zii.widgets.jui.CJuiDatePicker', array(
    'name'=>'publishDate',
    // additional jav开发者_如何转开发ascript options for the date picker plugin
    'options'=>array(
        'showAnim'=>'fold',
    ),
    'htmlOptions'=>array(
        'style'=>'height:20px;'
    ),
));

The form field is rendered, but when I click it nothing happens, no calendar is displayed. Am I missing something? do I have to manually include JQuery, or set some javascript callbacks or anything else than the example above?

I experienced the same when the corresponding CSS file was missing. The calendar did appear although far beyond the boundaries of the window.

Sorry, my fault.
There was a .htaccess with deny from all, preventing the page from loading the Jquery files from the /assets dir.
Thanks anyway!