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How to use PHP to verify username and password (code)

不言Original: 2018-07-24 11:43:252539browse

The content shared with you in this article is about using PHP to verify user names and passwords. The content is of great reference value and I hope it can help friends in need.

Login page 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>

Login verification, logout login login.php

<?php 
//登录  
if(!isset($_POST[&#39;submit&#39;])){  
    exit(&#39;非法访问!&#39;);  
}  
$username = htmlspecialchars($_POST[&#39;username&#39;]);  
$password = MD5($_POST[&#39;password&#39;]);  
   
//包含数据库连接文件  
include(&#39;conn.php&#39;);  
//检测用户名及密码是否正确  
$check_query = mysql_query("select userid from user_list where username=&#39;$username&#39; and password=&#39;$password&#39; limit 1");  
if($result = mysql_fetch_array($check_query)){  
    //登录成功  
    session_start();  
    $_SESSION[&#39;username&#39;] = $username;  
    $_SESSION[&#39;userid&#39;] = $result[&#39;userid&#39;];  
    echo $username,&#39; 欢迎你！进入 <a href="my.php">用户中心</a><br />&#39;;  
    echo &#39;点击此处 <a href="login.php?action=logout">注销</a> 登录！<br />&#39;;  
    exit;  
} else {  
    exit(&#39;登录失败！点击此处 <a href="javascript:history.back(-1);">返回</a> 重试&#39;);  
}  
   
   
   
//注销登录  
if($_GET[&#39;action&#39;] == "logout"){  
    unset($_SESSION[&#39;userid&#39;]);  
    unset($_SESSION[&#39;username&#39;]);  
    echo &#39;注销登录成功！点击此处 <a href="login.html">登录</a>&#39;;  
    exit;  
}  
   
?>

Login monitoring 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[&#39;userid&#39;])){  
    header("Location:login.html");  
    exit();  
}  
//包含数据库连接文件  
include(&#39;conn.php&#39;);  
$userid = $_SESSION[&#39;userid&#39;];  
$username = $_SESSION[&#39;username&#39;];  
$user_query = mysql_query("select * from user_list where userid = &#39;$userid&#39; limit 1");  
$row = mysql_fetch_array($user_query);  
echo &#39;用户信息：<br />&#39;;  
echo &#39;用户ID：&#39;,$userid,&#39;<br />&#39;;  
echo &#39;用户名：&#39;,$username,&#39;<br />&#39;;  
echo &#39;<a href="login.php?action=logout">注销</a> 登录<br />&#39;;  
?>

Connect to the database 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");  
?>

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