PHP development message board tutorial login function

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>欢迎登录</title>
    <style type="text/css">
        *{margin: 0px;padding: 0px;}
        body{background:#eee;}
        #div{width:300px;height:400px;background:#B1FEF9;margin:0 auto;margin-top:150px;
            border-radius:20px;}
        h3{margin-left:48px;padding-top:60px;}
        h4{margin-left:120px;padding-top:60px;font-size: 18px;}
        #cnt{width:280px;height:370px;margin-left:33px;padding-top:60px;}
        .sub{width:70px;height:30px;border:1px solid #fff;background:#eee;
            margin-left:28px;margin-top:20px;}
        .sub1{
            width:70px;height:30px;border:1px solid #fff;background:#eee;margin-left:150px;margin-top:20px;}
    </style>
</head>
<body>
    <div id="div">
        <h3>欢迎登陆后台管理系统</h3>
        <div id="cnt">
            <form method="post" action="main.php">
                用户名：<input type="text" placeholder="请输入用户名" name="username">
                <br><br>
                密&nbsp;码：<input type="password" placeholder="请输入密码" name="password">
                <br><br>
                <input type="submit" value="登录" class="sub">
            </form>
        </div>
    </div>
</body>
</html>

The form is submitted to main.php. Now let’s analyze main.php

After we log in, if we have a lot of There is no web page to operate on for a long period of time. When you operate again, you need to log in. This will use our session knowledge

First we need to open the session

session_start();

Then we need to introduce the file conn.php that links to the database.

require_once('conn.php');

Get the form information, and then save the form information Enter session

$name = $_POST['username'];
$pwd = md5($_POST['password']);
$_SESSION['name']=$name;
$_SESSION['pwd']=$pwd;

Let’s go to the database to query. If there is information submitted by the form in the database, then we should make the information submitted by the form available for login operations

$sql = "select * from user where username='$name' and password='$pwd'";
$info = mysql_query($sql);
$row = mysql_fetch_row($info );

Then judge $row, if it exists, the login is successful, jump to the homepage to add a message, otherwise, return to the page and log in again

if($row) {
echo " alert('Login failed')</script>";
echo "<script>location.href='login.php';</script>"; //Login failed, jump to another one Page
}

main.php The complete code is as follows:

<?php
    session_start();
    require_once('conn.php');
    $name = $_POST['username'];
    $pwd = md5($_POST['password']);
    $_SESSION['name']=$name;
    $_SESSION['pwd']=$pwd;
    $sql = "select * from user where username='$name' and password='$pwd'";
    $info = mysql_query($sql);
    $row = mysql_fetch_row($info);
    if($row){
        echo "<script>alert('登录成功');location.href='message.php';</script>";
    }else{
        echo "<script>alert('登录失败')</script>";
        echo "<script>location.href='login.php';</script>";  //登录失败，跳转到另外一个页面
    }

?>

Continuing Learning

new file

<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>欢迎登录</title> <style type="text/css"> *{margin: 0px;padding: 0px;} body{background:#eee;} #div{width:300px;height:400px;background:#B1FEF9;margin:0 auto;margin-top:150px; border-radius:20px;} h3{margin-left:48px;padding-top:60px;} h4{margin-left:120px;padding-top:60px;font-size: 18px;} #cnt{width:280px;height:370px;margin-left:33px;padding-top:60px;} .sub{width:70px;height:30px;border:1px solid #fff;background:#eee; margin-left:28px;margin-top:20px;} .sub1{ width:70px;height:30px;border:1px solid #fff;background:#eee;margin-left:150px;margin-top:20px;} </style> </head> <body> <div id="div"> <h3>欢迎登陆后台管理系统</h3> <div id="cnt"> <form method="post" action="main.php"> 用户名：<input type="text" placeholder="请输入用户名" name="username"> <br><br> 密码：<input type="password" placeholder="请输入密码" name="password"> <br><br> <input type="submit" value="登录" class="sub"> </form> </div> </div> </body> </html>

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PHP development message board tutorial login function

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