WordPress获取搜索表单函数get_search_form用法

function get_search_form( $echo = true ) {
/**
 * Fires before the search form is retrieved, at the start of get_search_form().
 *
 * @since 2.7.0 as 'get_search_form' action.
 * @since 3.6.0
 *
 * @link https://core.trac.wordpress.org/ticket/19321
 */
do_action( 'pre_get_search_form' );
$format = current_theme_supports( 'html5', 'search-form' ) ? 'html5' : 'xhtml';
/**
 * Filters the HTML format of the search form.
 *
 * @since 3.6.0
 *
 * @param string $format The type of markup to use in the search form.
 *                       Accepts 'html5', 'xhtml'.
 */
$format = apply_filters( 'search_form_format', $format );
$search_form_template = locate_template( 'searchform.php' );
if ( '' != $search_form_template ) {
ob_start();
require( $search_form_template );
$form = ob_get_clean();
} else {
if ( 'html5' == $format ) {
$form = '<form role="search" method="get" class="search-form" action="' . esc_url( home_url( '/' ) ) . '">
<label>
<span class="screen-reader-text">' . _x( 'Search for:', 'label' ) . '</span>
<input type="search" class="search-field" placeholder="' . esc_attr_x( 'Search &hellip;', 'placeholder' ) . '" value="' . get_search_query() . '" name="s" />
</label>
<input type="submit" class="search-submit" value="'. esc_attr_x( 'Search', 'submit button' ) .'" />
</form>';
} else {
$form = '<form role="search" method="get" id="searchform" class="searchform" action="' . esc_url( home_url( '/' ) ) . '">
<div>
<label class="screen-reader-text" for="s">' . _x( 'Search for:', 'label' ) . '</label>
<input type="text" value="' . get_search_query() . '" name="s" id="s" />
<input type="submit" id="searchsubmit" value="'. esc_attr_x( 'Search', 'submit button' ) .'" />
</div>
</form>';
}
}
/**
 * Filters the HTML output of the search form.
 *
 * @since 2.7.0
 *
 * @param string $form The search form HTML output.
 */
$result = apply_filters( 'get_search_form', $form );
if ( null === $result )
$result = $form;
if ( $echo )
echo $result;
else
return $result;
}

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

<?php get_search_form( $echo ); ?>