[Wiki] A simple way to get Yii client-side form validation run when submitting by ajax

$this->beginWidget('CActiveForm', array(
    ...
    'enableClientValidation'=>true,
    'clientOptions'=>array(
        'validateOnSubmit'=>true,
        'afterValidate'=>'js:$.yii.fix.ajaxSubmit.afterValidate'
    )
    ...
);

echo CHtml::ajaxSubmitButton('Whateverlabel', 'whateverurl', array(
    ...
    'beforeSend'=>'js:$.yii.fix.ajaxSubmit.beforeSend("#YOUR_FORM_ID")'
    ...
);

;$.yii.fix = {
    ajaxSubmit : {  
        beforeSend : function(form) {
            return function(xhr,opt) {
                form = $(form);
                $._data(form[0], "events").submit[0].handler();
                var he = form.data('hasError');
                form.removeData('hasError');
                return he===false;
            }
        },
 
        afterValidate : function(form, data, hasError) {
            $(form).data('hasError', hasError);
            return true;
        }
    }
};