Creating A Cjuidialog With Disabled Buttons

So this is an example I copied from YiiPlayground showing how to use a dialog with callback. Would there be an easy way to modify this so that "select" is disabled until a field in the dialog is filled in?

<?php $this->beginWidget('zii.widgets.jui.CJuiDialog', array(
       'id'=>'findClient',
        'options'=>array(
            'title'=>'Find Client',
            'autoOpen'=>false,
            'modal'=>true,
            'buttons'=>array(
                'Select'=>'js:addItem',
                'Cancel'=>'js:function(){ $(this).dialog("close");}',
            ),
        ),
)); ?>