网站构建三（身份验证）

使用PHP和MySQL实现了用户的用户的身份验证。

用户登录，实现用户输入与MySQL数据的匹配：

<?php$name=$_POST['username'];$password=$_POST['password'];if((!isset($name))||(!isset($password))){require("login.php");}else{$mysql=mysqli_connect("localhost","webauth","webauth");if(!$mysql){echo "Cannot connect to database.";exit;}$selected=mysqli_select_db($mysql,"auth");if(!$selected){echo "Cannot select database.";exit;}$query='select count(*) from authorized_users whereusernamesignup="'.$name.'"and passwordsignup="'.$password.'"';$result=mysqli_query($mysql,$query);if(!$result){echo "Cannot run query.";exit;}$row=mysqli_fetch_row($result);$count=$row[0];if($count>0){require("home.php");}else{echo "<h1>Go Away!</h1>  <p>You are not authorized to use this resourse.</p>";}}?>

用户注册，实现数据插入存储：

<?php$usernamesignup=$_POST['usernamesignup'];$emailsignup=$_POST['emailsignup'];$passwordsignup=$_POST['passwordsignup'];$passwordsignup_confirm=$_POST['passwordsignup_confirm'];if(!get_magic_quotes_gpc()){$usernamesignup=addslashes($usernamesignup);$emailsignup=addslashes($emailsignup);$passwordsignup=addslashes($passwordsignup);$passwordsignup_confirm=addslashes($passwordsignup_confirm);}if($passwordsignup==$passwordsignup_confirm){@$db=mysqli_connect("localhost","webauth","webauth");if(!$db){echo "Error:Could not connect to database.Please try again later.";exit;}$selected=mysqli_select_db($db,"auth");if(!$selected){echo "Cannot select database.";exit;}$query="insert into authorized_users values('".$usernamesignup."','".$emailsignup."','".$passwordsignup."','".$passwordsignup_confirm."')";$result=mysqli_query($db,$query);if($result){echo "user inserted into database.";}else{echo "An error has occurred.The item was not added.";}$db->close();}else{echo "Password doesn't match.Please enter the same values.";exit;}?>

待解决问题：如果同一个用户，多次注册，应该有对策。登陆后的相关页面显示也有待改进。