求壹個簡單的php登錄頁面代碼，只需要用戶名和密碼與數據庫中表裏面的信息相同就可以登錄的頁面代碼

$mysql_servername = "localhost";

$mysql_username = "數據庫用戶名";

$mysql_password ="密碼";

$mysql_database ="數據庫名";

mysql_connect($mysql_servername , $mysql_username , $mysql_password);

mysql_select_db($mysql_database);

$name=$_POST['user_name'];

$passowrd=$_POST['user_password'];

if ($name && $passowrd){

$sql = "SELECT * FROM admin WHERE name = '$name' and password='$passowrd'";

$res = mysql_query($sql);

$rows=mysql_num_rows($res);

if($rows){

header("location='主頁'");

exit;

}

echo "<script language=javascript>alert('用戶名密碼錯誤');history.back();</script>";

}else {

echo "<script language=javascript>alert('用戶名密碼不能為空');history.back();</script>";

}