  <form class="form-group" role="search" method="get" id="searchform" action="<?php echo esc_url(home_url( '/' )); ?>">
   <input type="text" value="" class="form-control"  name="s" id="s">
   <input type="submit" class="btn btn-primary" id="searchsubmit" value="<?php echo esc_attr_x( 'Search', 'submit button' ); ?>" />
  </form>