codeigniter dynamic css and js

dinamic_css_js.php

//credit http://jamshidhashimi.com/2013/04/12/dynamically-add-javascript-and-css-files-in-codeigniter-header-page/
// add to config
$config['header_css'] = array('style.css','prettyPhoto.css','nivo-slider.css');
$config['header_js']  = array('core.js','core.js',
                              'jquery-1.4.1.min.js',
                              'jquery-slidedeck.pack.lite.js',
                              'jquery-prettyPhoto.js',
                              'jquery.nivo.slider.js');

// add to function helper
//Dynamically add Javascript files to header page
if(!function_exists('add_js')){
    function add_js($file='')
    {
        $str = '';
        $ci = &get_instance();
        $header_js  = $ci->config->item('header_js');

        if(empty($file)){
            return;
        }

        if(is_array($file)){
            if(!is_array($file) && count($file) <= 0){
                return;
            }
            foreach($file AS $item){
                $header_js[] = $item;
            }
            $ci->config->set_item('header_js',$header_js);
        }else{
            $str = $file;
            $header_js[] = $str;
            $ci->config->set_item('header_js',$header_js);
        }
    }
}

//Dynamically add CSS files to header page
if(!function_exists('add_css')){
    function add_css($file='')
    {
        $str = '';
        $ci = &get_instance();
        $header_css = $ci->config->item('header_css');

        if(empty($file)){
            return;
        }

        if(is_array($file)){
            if(!is_array($file) && count($file) <= 0){
                return;
            }
            foreach($file AS $item){   
                $header_css[] = $item;
            }
            $ci->config->set_item('header_css',$header_css);
        }else{
            $str = $file;
            $header_css[] = $str;
            $ci->config->set_item('header_css',$header_css);
        }
    }
}

if(!function_exists('put_headers')){
    function put_headers()
    {
        $str = '';
        $ci = &get_instance();
        $header_css = $ci->config->item('header_css');
        $header_js  = $ci->config->item('header_js');

        foreach($header_css AS $item){
            $str .= '<link rel="stylesheet" href="'.base_url().'css/'.$item.'" type="text/css" />'."\n";
        }

        foreach($header_js AS $item){
            $str .= '<script type="text/javascript" src="'.base_url().'js/'.$item.'"></script>'."\n";
        }

        return $str;
    }
}

//set in view
add_css(array('jamshid.css','hashimi.css'));
add_js('jamshid.js');

Thank's for such a great code you had share.