different between ajaxButton and submitButton(ajax)

i was just wondering if is there a different between this 2 things …

<?php echo CHtml::beginForm(); ?>


	<div class="row buttons">

		<?php echo CHtml::submitButton('Ipod',


		'ajax' => array(

		'type'=>'POST', //request type

		'url'=>"/yii_new/HelloWorld/index.php?r=HelloWorld/erg", //url to call




		); ?>


		 <?php echo CHtml::ajaxButton ("Update data",


          array('update' => '#erg', 'type' => 'POST'));




<?php echo CHtml::endForm(); ?>

The only difference I see is that the previous is a submit button, and so is activated if a user press enter in a text-box, for example, and the latter no.

But actually they are nearly the same