问如何在Codeigniter中使用GET方法

EN

<?=form_open(base_url(), array('id' => 'search'))?>
    <input type="text" class="form-control" placeholder="Keyword..." name="query" id="search_query">
    <button class="btn btn-default" id="btn-search" type="button">
        Search
    </button>
<?=form_close()?>

$("#btn-search").click(function(){
    var query = $("#search_query").val();
    window.location = '/search/'+query;
});

$('form#search').bind("keypress", function(e) {
    if (e.keyCode == 13) {
        e.preventDefault();
        var query = $("#search_query").val();
        return window.location = '/search/'+query;
    }
});

$route['search/(:any)'] = 'Controller/search/$1';

public function search($keyword = null)
{
    if($keyword == null)
        redirect(base_url());
    else
    {
        $keyword = urldecode($keyword);
        $data = array(
            'category' => $this->Category_Model->search($keyword)
        );
        $this->load->view('search', $data);
    }
}