Wordpress Widget jquery live() or on(), admin side

[admin]

something disturbing me since a while, jQuery API says :

As of jQuery 1.7, the .live() method is deprecated. Use .on() to attach event handlers.

As I try to add some jquery stuff in my widget admin side ( <em>form() action of widget class</em> ), I was surprise to not be able to use on(), but live() to do the job.

So here is my question : <strong>Why and what am I misunderstanding ?</strong>

Regards, and of course, thx for your time.

ps I'm offcurse using >= 1.7 version.

Edit:

<?php
    class Test_Slider_Widget extends WP_Widget 
        { 
            public function form( $instance ) { 
                ?>
             <span id="test">Test</span>
             <script> 
             jQuery(document).ready(function($) {
                 /* $('#test').on('click', function { //doesn't work
                     alert('test'); 
                 }); */
                 $('#test').live('click', function { //work
                     alert('test');
                 });

             });
             </script>


 <?php }

EDIT 2: Ok, always use $this->get_field_id('id-text') to have a unique ID, or id will be duplicated cause of widget duplicated code in wordpress admin.
Thanks to <strong>Xec</strong> for showing me the way