隔了几年又接触了CI框架，需要做个AJAX分页，以前也就是懂个皮毛，现在是现学活用了。

首先来个正常分页的demo

public function querylog(){
    $data = [];

    if(!empty($_GET["stime"])){
        $current_url= 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
    }
    else{
        $current_url= 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'].'?noparam=1';
    }

    !empty($_GET["user"]) && $this->db->where("user",$_GET["user"]);
    !empty($_GET["host"]) && $this->db->where("host",$_GET["host"]);
    $stime = !empty($_GET["stime"])? $_GET["stime"]: date('Y-m-d H:i',time()-3600*24*30);
    $etime = !empty($_GET["etime"])? $_GET["etime"]: date('Y-m-d H:i',time()+60);
    $this->db->where("create_time >=",$stime);
    $this->db->where("create_time <=",$etime);

    // 分页
    $this->load->library('pagination');
    $config['base_url'] = $current_url;
    $config['total_rows'] = $this->log->get_total_rows();
    $config['per_page'] = 30;
    $config['num_links'] = 5;
    $config['page_query_string'] = TRUE;
    $config['use_page_numbers'] = TRUE;
    $this->pagination->initialize($config);
    $offset = !empty($_GET['per_page']) ? $_GET['per_page'] : 1;

    !empty($_GET["user"]) && $this->db->where("user",$etime);
    $this->db->order_by("id","desc");
    $data['datalist'] = $this->log->get_total_record_paging($config['per_page'],($offset-1)*$config['per_page']);

    $setval["host"]=isset($_GET["host"]) ? $_GET["host"] : "";
    $setval["user"]=isset($_GET["user"]) ? $_GET["user"] : "";
    $setval["stime"]=$stime;
    $setval["etime"]=$etime;
    $data["setval"]=$setval;

    $this->layout->view("inception/querylog",$data);
}

/**
 * Generate the pagination links
 *
 * @access    public
 * @return    string
 */
function create_ajax_links()
{
    // If our item count or per-page total is zero there is no need to continue.
    if ($this->total_rows == 0 OR $this->per_page == 0)
    {
        return '';
    }

    // Calculate the total number of pages
    $num_pages = ceil($this->total_rows / $this->per_page);

    // Is there only one page? Hm... nothing more to do here then.
    if ($num_pages == 1)
    {
        return '';
    }

    // Set the base page index for starting page number
    if ($this->use_page_numbers)
    {
        $base_page = 1;
    }
    else
    {
        $base_page = 0;
    }

    // Determine the current page number.
    $CI =& get_instance();

    if ($CI->config->item('enable_query_strings') === TRUE OR $this->page_query_string === TRUE)
    {
        if ($CI->input->get($this->query_string_segment) != $base_page)
        {
            $this->cur_page = $CI->input->get($this->query_string_segment);

            // Prep the current page - no funny business!
            $this->cur_page = (int) $this->cur_page;
        }
    }
    else
    {
        if ($_REQUEST['page'] != $base_page)
        {
            $this->cur_page = $_REQUEST['page'];

            // Prep the current page - no funny business!
            $this->cur_page = (int) $this->cur_page;
        }
    }

    // Set current page to 1 if using page numbers instead of offset
    if ($this->use_page_numbers AND $this->cur_page == 0)
    {
        $this->cur_page = $base_page;
    }

    $this->num_links = (int)$this->num_links;

    if ($this->num_links < 1)
    {
        show_error('Your number of links must be a positive number.');
    }

    if ( ! is_numeric($this->cur_page))
    {
        $this->cur_page = $base_page;
    }

    // Is the page number beyond the result range?
    // If so we show the last page
    if ($this->use_page_numbers)
    {
        if ($this->cur_page > $num_pages)
        {
            $this->cur_page = $num_pages;
        }
    }
    else
    {
        if ($this->cur_page > $this->total_rows)
        {
            $this->cur_page = ($num_pages - 1) * $this->per_page;
        }
    }

    $uri_page_number = $this->cur_page;

    if ( ! $this->use_page_numbers)
    {
        $this->cur_page = floor(($this->cur_page/$this->per_page) + 1);
    }

    // Calculate the start and end numbers. These determine
    // which number to start and end the digit links with
    $start = (($this->cur_page - $this->num_links) > 0) ? $this->cur_page - ($this->num_links - 1) : 1;
    $end   = (($this->cur_page + $this->num_links) < $num_pages) ? $this->cur_page + $this->num_links : $num_pages;

    // Is pagination being used over GET or POST?  If get,add a per_page query
    // string. If post,add a trailing slash to the base URL if needed
    if ($CI->config->item('enable_query_strings') === TRUE OR $this->page_query_string === TRUE)
    {
        $this->base_url = rtrim($this->base_url).'&'.$this->query_string_segment.'=';
    }
    else
    {
        $this->base_url = rtrim($this->base_url,'/') .'/';
    }

    // And here we go...
    $output = '';

    // Render the "First" link
    if  ($this->first_link !== FALSE AND $this->cur_page > ($this->num_links + 1))
    {
        $first_url = ($this->first_url == '') ? $this->base_url : $this->first_url;
        $output .= $this->first_tag_open.'<a '." onclick='ajax_page(0);return false;'".$this->anchor_class.'href="javascript:void(0)">'.$this->first_link.'</a>'.$this->first_tag_close;
    }

    // Render the "prevIoUs" link
    if  ($this->prev_link !== FALSE AND $this->cur_page != 1)
    {
        if ($this->use_page_numbers)
        {
            $i = $uri_page_number - 1;
        }
        else
        {
            $i = $uri_page_number - $this->per_page;
        }

        if ($i == 0 && $this->first_url != '')
        {
            $output .= $this->prev_tag_open.'<a '." onclick='ajax_page(0);return false;'".$this->anchor_class.'href="javascript:void(0)">'.$this->prev_link.'</a>'.$this->prev_tag_close;
        }
        else
        {
            $i = ($i == 0) ? '' : $this->prefix.$i.$this->suffix;
            $output .= $this->prev_tag_open.'<a '." onclick='ajax_page({$i});return false;'".$this->anchor_class.'href="javascript:void(0)">'.$this->prev_link.'</a>'.$this->prev_tag_close;
        }

    }

    // Render the pages
    if ($this->display_pages !== FALSE)
    {
        // Write the digit links
        for ($loop = $start -1; $loop <= $end; $loop++)
        {
            if ($this->use_page_numbers)
            {
                $i = $loop;
            }
            else
            {
                $i = ($loop * $this->per_page) - $this->per_page;
            }

            if ($i >= $base_page)
            {
                if ($this->cur_page == $loop)
                {
                    $output .= $this->cur_tag_open.$loop.$this->cur_tag_close; // Current page
                }
                else
                {
                    $n = ($i == $base_page) ? '' : $i;

                    if ($n == '' && $this->first_url != '')
                    {
                        $output .= $this->num_tag_open.'<a '." onclick='ajax_page(0);return false;'".$this->anchor_class.'href="javascript:void(0)">'.$loop.'</a>'.$this->num_tag_close;
                    }
                    else
                    {
                        $n = ($n == '') ? '' : $this->prefix.$n.$this->suffix;

                        $output .= $this->num_tag_open.'<a '." onclick='ajax_page({$n});return false;'".$this->anchor_class.'href="javascript:void(0)">'.$loop.'</a>'.$this->num_tag_close;
                    }
                }
            }
        }
    }

    // Render the "next" link
    if ($this->next_link !== FALSE AND $this->cur_page < $num_pages)
    {
        if ($this->use_page_numbers)
        {
            $i = $this->cur_page + 1;
        }
        else
        {
            $i = ($this->cur_page * $this->per_page);
        }
        $ajax_p = $this->prefix.$i.$this->suffix;
        $output .= $this->next_tag_open.'<a '." onclick='ajax_page({$ajax_p});return false;'".$this->anchor_class.'href="javascript:void(0)">'.$this->next_link.'</a>'.$this->next_tag_close;
    }

    // Render the "Last" link
    if ($this->last_link !== FALSE AND ($this->cur_page + $this->num_links) < $num_pages)
    {
        if ($this->use_page_numbers)
        {
            $i = $num_pages;
        }
        else
        {
            $i = (($num_pages * $this->per_page) - $this->per_page);
        }
        $ajax_p = $this->prefix.$i.$this->suffix;
        $output .= $this->last_tag_open.'<a '." onclick='ajax_page({$ajax_p});'". $this->anchor_class.'href="javascript:void(0)">'.$this->last_link.'</a>'.$this->last_tag_close;
    }

    // Kill double slashes.  Note: Sometimes we can end up with a double slash
    // in the penultimate link so we'll kill all double slashes.
    $output = preg_replace("#([^:])//+#","\\1/",$output);

    // Add the wrapper HTML if exists
    $output = $this->full_tag_open.$output.$this->full_tag_close;

    return $output;
}