CFileUpload don't works with ajax

I have a form like

<?php echo FHtml::form(’’,‘post’,array(‘enctype’=>‘multipart/form-data’)); ?>

with an an activeFileField inside.

The ajaxButton don’t submit the file, but only the other data (textfield, checkbox etc), while a normal submit button like

<?php echo FHtml::submitButton(‘sub’);?>

Is it a bug or there is something more to do in ajaxButton?

ajax can not transfer multipart mode~

so,you should be use iframe or flash, etc to imitate "ajax" to upload file~

thank you very much. I will do in other way