WordPress: Dynamic sidebar

sidebar.php

<?php if(dynamic_sidebar('wp-sidebar')) : else : ?>
    <div class="widget widget_search">
        <h4>Search</h4>
        <?php get_search_form(); ?>
    </div><!-- END WIDGET -->
    <div class="widget widget_categories">
        <h4>Categories</h4>
        <ul>
            <?php wp_list_categories('title_li='); ?>
        </ul>
    </div><!-- END WIDGET -->
    <div class="widget widget_archive">
        <h4>Archives</h4>
        <ul>
            <?php wp_get_archives(); ?>
        </ul>
    </div><!-- END WIDGET -->
    <div class="widget widget_tag_cloud">
        <h4>Tags</h4>
        <div class="tagcloud">
        <?php wp_tag_cloud(); ?>
        </div>
    </div><!-- END WIDGET -->
<?php endif; ?>