PHP登录程序

【摘自网络，参考学习】

添加了MD5加密

<?php
error_reporting(0);

$mysql_servername = ""; //主机地址
$mysql_username = ""; //数据库用户名
$mysql_password =""; //数据库密码
$mysql_database =""; //数据库
mysql_connect($mysql_servername , $mysql_username , $mysql_password);
mysql_select_db($mysql_database);
$name=$_POST['name'];
$password=$_POST['password'];
$VerificationCode=$_POST['check'];

//MD5加密
$md5password=md5($password);

//验证验证码
if($VerificationCode!=$_SESSION['VerifyCode']){
echo "<script language=javascript>alert('验证码错误！');history.back();</script>";
}

//验证用户名和密码
if ($name && $password){
$sql = "SELECT * FROM admin WHERE admin_name = '$name' and admin_pw='$md5password'";
$res = mysql_query($sql);
$rows=mysql_num_rows($res);
if($rows){
//定义session
session_start();
$_SESSION['admin_name']=$name;

header("refresh:0;url=../index.php");//跳转页面，注意路径
exit;
}
echo "<script language=javascript>alert('用户名密码错误');history.back();</script>";
}else {
echo "<script language=javascript>alert('用户名密码不能为空');history.back();</script>";
}

?>