Wordpress中的Ajax请求总是在管理端执行，所以is_admin() 返回始终为true。如果需要知道ajax请求来自何处，则需要检查脚本的执行位置，而不是脚本发送ajax请求的位置。

例如：

add_action(\'wp_enqueue_scripts\', \'cyb_enqueue_scripts\');
function cyb_enqueue_scripts() {

    //Register the script.
    wp_register_script(\'my-script\', get_stylesheet_directory_uri(). \'/js/my-script.js\', array( \'jquery\' ) );

    //Enqueue the script and dependencies
    wp_enqueue_script(\'jquery\');
    wp_enqueue_script(\'my-script\');

    //Set up the vars data for the script
    $scriptvars = array(
                    \'ajaxurl\' => admin_url( \'admin-ajax.php\' ),
                    \'data\'    => array(
                                  \'action\'   => \'get_something\',
                                  \'is_admin\' => is_admin()
                             )
                   );
    wp_localize_script(\'my-script\', \'script_vars\', $scriptvars);
}


add_action( \'wp_ajax_get_something\', \'get_something\');
add_action( \'wp_ajax_nopriv_get_something\', \'get_something\');

function get_something(){

    if( isset($_POST[\'is_admin\']) && $_POST[\'is_admin\'] == true ) {
        //The ajax request comes from admin area
        $is_admin = true;
    } else {
        $is_admin = false;
    }

    $data = array( \'is_admin\' => $is_admin );
    wp_send_json_success( $data );

}

(function($){
    $(document).ready(function(){
        jQuery.ajax({
            url: script_vars.ajaxurl,
            data: script_vars.data,
            type: \'post\',
            success: function(response){
                alert(response.data.is_admin);
            }
         });
    });
})(jQuery);