click event not firing on elements inside thickbox

In my plugin I am using thick box modal window to show the list of items. The content in the thickbox div is generated through a ajax request. I have input checkboxes inside this div. The click event on these check boxes are not triggered.

Here is my code:

<div id="wpb_media_tracks_container">    //This div is loaded into the thickbox and contents of this table are dynamically generated through ajax request
    <table class="wp_media_tracks_table">   
         <thead>
            <tr>
                <th>Choose tracks</th>
                <th>Filename</th>
                <th>Title</th>
            </tr>
        </thead>
        <tbody>
            <tr valign="top">
                <td scope="row">
                   <input type="checkbox" name="1522" value="1522">
                </td>
                <td>raagrang.mp3</td>
                <td>raagrang</td>
             </tr>
         </tbody>
     </table>
 </div>

jQuery code:

jQuery('.wp_media_tracks_table input').on("click", function() {

    postId = jQuery(this).val();
    alert(postId);
});

I also tried using this selectotr: jQuery('#wpb_media_tracks_container input'). But no results.

Can any one help me find the issue in my code?

Thanks,