PHP——登录验证与检测

本文给大家讲述的是使用PHP进行用户名和密码的验证，详细讲解了PHP如何连接数据库并且如何和从数据库查询数据并且验证，希望可以给大家学习PHP带来帮助。

登录页面 login.html

<html>  
<head>用户登录</head>  
<form name="LoginForm" method="post" action="login.php" onSubmit="return InputCheck(this)">  
<p>  
<label for="username" class="label">用户名:</label>  
<input id="username" name="username" type="text" class="input" />  
<p/>  
<p>  
<label for="password" class="label">密 码:</label>  
<input id="password" name="password" type="password" class="input" />  
<p/>  
<p>  
<input type="submit" name="submit" value="  确 定  " class="left" />  
</p>  
</form>  
</html>

登录验证、注销登录 login.php

<?php 
//登录  
if(!isset($_POST['submit'])){  
    exit('非法访问!');  
}  
$username = htmlspecialchars($_POST['username']);  
$password = MD5($_POST['password']);  
   
//包含数据库连接文件  
include('conn.php');  
//检测用户名及密码是否正确  
$check_query = mysql_query("select userid from user_list where username='$username' and password='$password' limit 1");  
if($result = mysql_fetch_array($check_query)){  
    //登录成功  
    session_start();  
    $_SESSION['username'] = $username;  
    $_SESSION['userid'] = $result['userid'];  
    echo $username,' 欢迎你！进入 <a href="my.php">用户中心</a><br />';  
    echo '点击此处 <a href="login.php?action=logout">注销</a> 登录！<br />';  
    exit;  
} else {  
    exit('登录失败！点击此处 <a href="javascript:history.back(-1);">返回</a> 重试');  
}  
   
   
   
//注销登录  
if($_GET['action'] == "logout"){  
    unset($_SESSION['userid']);  
    unset($_SESSION['username']);  
    echo '注销登录成功！点击此处 <a href="login.html">登录</a>';  
    exit;  
}  
   
?>

登录监测 my.php

<?php  
session_start();  
   
//检测是否登录，若没登录则转向登录界面  
if(!isset($_SESSION['userid'])){  
    header("Location:login.html");  
    exit();  
}  
//包含数据库连接文件  
include('conn.php');  
$userid = $_SESSION['userid'];  
$username = $_SESSION['username'];  
$user_query = mysql_query("select * from user_list where userid = '$userid' limit 1");  
$row = mysql_fetch_array($user_query);  
echo '用户信息：<br />';  
echo '用户ID：',$userid,'<br />';  
echo '用户名：',$username,'<br />';  
echo '<a href="login.php?action=logout">注销</a> 登录<br />';  
?>

连接数据库 conn.php

<?php
 $conn = mysql_connect("127.0.0.1","root","") or die("数据库链接错误".mysql_error());  
 mysql_select_db("info_db",$conn) or die("数据库访问错误".mysql_error());  
 mysql_query("set names gb2312");  
?>

PHP——登录验证与检测

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