Yii的AJAX活动

How can I attach an action to a checkbox or a select, that will be executed every time I click the checkbox or select the option?
I need this to perform an AJAX request.

Use this:

$("input[type='checkbox']").click(function(){
//code for ajax request
});

in the code for ajax request, if you want to know whether the checkbox is checked, use $(this).is(':checked')

Assuming you're using CHtml::checkBox() to generate the checkbox, an example would be:

CHtml::checkBox($name, false, array ('ajax'=>array(
                                        'type'=> 'POST',
                                        'url' => $url,
                                        'success'=> 'function(data) {
                                                        // callback function code here
                                                     }'
                )))

Details about the Yii ajax array