wordpress: search short code

gistfile1

<?php
//add_shortcode('wpbsearch', 'get_search_form');
function wpbsearchform( $form ) {

    $form = '<form role="search" method="get" id="searchform" action="' . home_url( '/' ) . '" >
    <div><label class="screen-reader-text" for="s">' . __('Search for:') . '</label>
    <input type="text" value="' . get_search_query() . '" name="s" id="s" />
    <input type="submit" id="searchsubmit" value="'. esc_attr__('Search') .'" />
    </div>
    </form>';

    return $form;
}
add_shortcode('wpbsearch', 'wpbsearchform');