Enable And Disable Image Button

In the yii form have a checkbox for agree conditions. The code like this

<div class="row">                     

<?php echo $form->checkBox($model,'agree',array('id'=>'abc')); ?>

<?php echo $form->labelEx($model, 'agree'); ?>

<?php echo "<br><br>".$form->error($model,'agree'); ?>


<div class="row buttons" >

<?php  echo CHtml::imageButton(Yii::app()->request->baseUrl.'/images/home/Create.png',      array('submit'),array('id'=>'efg'));?></div>

I want to disabled image button onload and when check the checkbox, i want to enable the image button. How it possible ?