How to show image in textbox?

How to show image in textbox?

PHP Code or Html:

<?php  echo $this->Form->text('Asr.search',array('id'=>'search','class'=>'search_icon')); ?>

Css Code :

#rbtm_feature .webTable .add .search_icon {
background:#FFFFFF url(../../img/front/search.png) no-repeat 4px 4px;
        padding:4px 4px 4px 22px;
        height:18px;
-webkit-border-radius: 8px;
-moz-border-radius: 8px;
border-radius: 8px;
width:150px;
}