用戶退出註銷操作
對於已經登入的使用者進行登出操作，介面如下：
#點選註銷進行session的銷毀操作，清空session裡的內容，銷毀一個會話中的全部數據，銷毀PHPSESSID與cookie的聯繫，操作成功介面如下：
##程式碼如下：
logout.php
<?php
/**
* Created by PhpStorm.
* User: Administrator
* Date: 2018/2/27 0027
* Time: 上午 11:44
*/
header('Content-type:text/html;charset=utf-8');
session_start();
if(isset($_SESSION['username'])){
// var_dump(session_name());die();
session_unset($_SESSION['username']);
session_destroy();//销毁一个会话中的全部数据
setcookie(session_name(),'');//销毁与客户端的联系
echo "<script>alert('注销成功！');location.href='login.html';</script>";
}else{
echo "<script>alert('注销失败！');</script>";
}
#下一節
<?php
/**
* Created by PhpStorm.
* User: Administrator
* Date: 2018/2/27 0027
* Time: 上午 10:47
*/
header('Content-type:text/html;charset=utf-8');
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
if (empty($_POST['username'])){
echo "<script>alert('用户名不能为空！');location.href='login.html';</script>";
}else {
$username=$_POST['username'];
}
if (empty($_POST['password'])){
echo "<script>alert('密码不能为空！');location.href='login.html';</script>";
}else{
$password=$_POST['password'];
}
}
$mysqli = new mysqli('localhost', 'root', 'root', 'student');
$result = $mysqli->query("SELECT password FROM user WHERE username = "."'$username'");
$rs=$result->fetch_row();
if (!empty($rs)){
if ($password != $rs[0]) {
echo "<script>alert('密码错误！');location.href='login.html';</script>";
}else{
$expire=3600;
ini_set('session.gc_maxlifetime', $expire);//保存1小时
if (empty($_COOKIE['PHPSESSID'])) {
session_set_cookie_params($expire);
session_start();
}else{
session_start();
setcookie('PHPSESSID', session_id(), time() + $expire);
}
if(isset($_SESSION['username'])){
exit("您已经登入了，请不要重新登入！用户名：{$_SESSION['username']}---<a href='logout.php'>注销</a>");
}else{
$_SESSION['username']=$_POST['username'];
}
echo "<script>alert('登录成功！');</script><br>";
echo "您好！{$_SESSION['username']},欢迎回来！";
echo "<a href='logout.php'>注销</a>";
}
}else{
echo "<script>alert('没有此用户！');location.href='login.html';</script>";
}
