Sample WordPress AJAX

/**
 * ------------------ PAGE 1 bcw.php ------------------
 */
<?php
/**
 * sets up AJAX capability
 *
 * enqueues the needed jQuery script and creates a local ajax object for the script.
 * registers and enqueues the CSS for the AJAX capable elements
 *
 * @parm string current admin page $hook
 */
function bcw_enqueue($hook) {
    if( 'edit-comments.php' != $hook)   // Only applies to comments list
        return;
    $email_nonce = wp_create_nonce( 'bcw_comment_email' );
    wp_enqueue_script( 'ajax-script', plugins_url( '/js/bcw.js', __FILE__ ),
         array('jquery'));
    // in javascript, array elements are accessed as ajax_object.ajaxurl,
    //   ajax_object.email, etc.
    wp_localize_script( 'ajax-script', 'ajax_object',
        array( 'ajaxurl' => admin_url( 'admin-ajax.php' ), 'email'=>$email_nonce )
    );
}
add_action( 'admin_enqueue_scripts', 'bcw_enqueue' );

/**
 * toggles email setting for comments
 *
 * no return - dies
 */
function bcw_toggle_email() {
    $commentid = $_POST['commentid'];       // getting variables from ajax post
    check_ajax_referer('bcw_comment_email');    // die if not correct referer
    if (current_user_can('moderate_comments')) {
        $reply = get_comment_meta( $commentid, 'bcw_email_reply', true );
        // prepare nonce for next request
        $email_nonce = wp_create_nonce( 'bcw_comment_email' );
        // Toggle the current setting
        if ($reply == 'Yes') {
            update_comment_meta($commentid, 'bcw_email_reply', 'x');
            echo 'x,' . $email_nonce;
        } else {
            update_comment_meta($commentid, 'bcw_email_reply', 'Yes');
            echo 'Yes,' . $email_nonce;
        }
    } else echo '!,' . $email_nonce;
    die(); // stop executing script
}
add_action( 'wp_ajax_email_action', 'bcw_toggle_email' ); // ajax for logged in users
?>


/**
 *  ------------- PAGE 2 bcw.js ------------------------
 */
 /**
 * javascript for BCW customizations
 */
jQuery(function($){
    // toggle email comment setting
    $("td.email.column-email").click(function () {
        var td = this;
        $.post(ajax_object.ajaxurl, {       //POST an AJAX request
            action: "email_action",
            commentid: $(this).find("input.commentid").attr("value"),
            //This nonce can only be used this one time
            _ajax_nonce: ajax_object.email
        }, function(data) {         //Handle AJAX response
            //includes email setting plus hidden comment id field
            var child = $(td).html();
            data = data.split(',');
            //save new nonce from server for next request
            ajax_object.email = data[1];
            //replace current value with new and add on the hidden comment id field
            var sym = child.split('<');
            $(td).html(data[0] + '<' + sym[1]);
        });
    });

})