21段救命PHP代码(8)

                {
                        $ip=$_SERVER['HTTP_CLIENT_IP'];
                }
                elseif (!emptyempty($_SERVER['HTTP_X_FORWARDED_FOR']))
                //to check ip is pass from proxy
                {
                        $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
                }
                else
                {
                        $ip=$_SERVER['REMOTE_ADDR'];
                }
                return $ip;
        }
　11. PHP强制性文件下载
　　为用户提供强制性的文件下载功能。
        /********************
        *@file - path to file
        */
        function force_download($file)
        {
        if ((isset($file))&&(file_exists($file))) {
        header("Content-length: ".filesize($file));
        header('Content-Type: application/octet-stream');
        header('Content-Disposition: attachment; filename="' . $file . '"');
        readfile("$file");
        } else {
        echo "No file selected";
        }
        }
12. PHP创建标签云
        function getCloud( $data = array(), $minFontSize = 12, $maxFontSize = 30 )
        {