一个基于mysql的登陆验证程序_PHP

/******************************************************
file name: login.php3
Login Check
编码： PHP 4
作者： Kevin Lee < webwing@21cn.com >

Database: MySQL。
Host: localhost Database : mydb
Table structure for table 'user'
--------------------------------------------------------
CREATE TABLE user (
id smallint(6) NOT NULL auto_increment,
user varchar(12) NOT NULL,
passwd varchar(12) NOT NULL,
name varchar(20),
email varchar(30),
level char(1),
status char(1),
UNIQUE id (id)
);
--------------------------------------------------------


*******************************************************/
?>

$db_id = mysql_pconnect("localhost", "root", "");
$sql="select id, user, passwd from user where user='".$name."' and passwd='".$pwd."'";
$result = mysql_db_query("mydb",$sql);
$row = mysql_fetch_array($result);
$id = $row[id] ;

if ($id!="") {
session_start();
session_register("yn");
$yn="yes" ;
echo "";
echo "你已经成功登陆。。。"."

";
echo "

"."窗口10秒钟后自动关闭"."";
echo "";

}
else {
echo "帐号或密码错误！！！";
echo "

";
echo "

";
echo "back";
echo "" ;
}
?>