<form action="<?php esc_url( home_url( '/' ) ); ?>" id="searchform" method="get">
    <fieldset><legend> <?php _e('Find Articles', 'tswplain'); ?> </legend>
        <label for="s" class="screen-reader-text"><?php _e('Search for: ', 'tswplain'); ?></label>
        <input type="text" id="s" name="s" value="" />       
        <input type="submit" value="<?php _e('Search', 'tswplain'); ?>" id="searchsubmit" />
    </fieldset>
</form>