//自动为用户随机生成用户名(长度6-13) 

        function create_password($pw_length = 4){ 

            $randpwd = ”; 

            for ($i = 0; $i < $pw_length; $i++){ 

                $randpwd .= chr(mt_rand(33, 126)); 

            } 

            return $randpwd; 

        } 

        function generate_username( $length = 6 ) { 

            // 密码字符集,可任意添加你需要的字符 

            $chars = ‘abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()-_ []{}<>~`+=,.;:/?|’; 

            $password = ”; 

            for ( $i = 0; $i < $length; $i++ ) 

            { 

                // 这里提供两种字符获取方式 

                // 第一种是使用substr 截取$chars中的任意一位字符; 

                // 第二种是取字符数组$chars 的任意元素 

                // $password .= substr($chars, mt_rand(0, strlen($chars) – 1), 1); 

                $password .= $chars[ mt_rand(0, strlen($chars) – 1) ]; 

            } 

            return $password; 

        } 

        // 调用该函数 

        $userid = ‘user’.generate_username(6); 

        $pwd = create_password(9); 

 

摘自 hurry的专栏