HTML+PHP+MYSQL实现一个简单-网站制作-设计策划-资讯-招财猫企服

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大家好，下面将为大家展示基于HTML PHP 的留言板的设计与实现过程，适合初学者点击观看，以下我将会以笔者自称！

 废话不多说，进入正题！

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文章目录

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###此留言版共可分为两个模块

创建数据表代码的实现

——以下是留言板的实现

提示：以下是本篇文章正文内容，下面案例可供参考

一、创建数据表（1）打开

打开我们已经配置好的，在软件管理中找到.3,点击安装并打开

（2）创建数据库

进来之后，鼠标右键点击，新建新的数据库，我们取名为

（3）创建数据表和字段

右键，新建三张数据表

1.第一张数据表为里边包含七个字段，是用来存储普通用户的注册信息的。

2.第二张数据表为里边包含四个字段，是用来存储管理员的信息的。字段默认值设为0，并手动添加一组数据，例：和均为，将值设为1。

疑问：为何单设一组数据令值为1？

解疑：后续代码中呢，会令值为1的数据成为站主，只有站主才能将表中普通用户信息，添加到表中，实现设置管理员的功能，保证了设置管理员的权限掌握在站主手中。

3.第二张数据表为里边包含三个字段，是用来存储用户留言内容的。

二，代码的实现 1.登录页面

前端 .html

DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>登录页面title>
head>
<script>
    //用户名和密码不能为空
function checkform() {
    $user_name = document.getElementById("username").value;
    $user_pwd = document.getElementById("password").value;
    if ($user_name == '') {
        alert("用户名不能为空");
        username.value = "";
        return;
        // window.history.go(-1);
    }
    if ($user_pwd == '') {
        alert("密码不能为空");
        password.value = "";
        return;
        // window.history.go(-1);
    }
}
script>
<body>
    <h1 align="center">欢迎您的访问！h1>
    <form method="POST" action="loginpage.php" align="center">
        用户名：<input type="text" name="username" id="username" placeholder="请输入用户名"><br/>
        密　码：<input type="password" name="password" id="password" placeholder="请输入密码"><br>
        <input type="submit"value="登录" onclick="checkform()">
        <p>
    <a href="register.html"><input type="button" value='注册'>a>
    <a href="admin.html"><input type="button" value='管理员登录'>a>
    form>
html>

后端 .php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>登录页面</title>
</head>
<body>
    <?php
    $username = $_POST['username'];
    $password = $_POST['password'];
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select* from admin where username='$username' and password='$password'";
    $result = mysqli_query($link,$sql) or die('信息读取失败');
    $a = mysqli_fetch_array($result);
    if($a['username']==$username && $username!='' && $a['password']==$password && $password!=''){
        session_start();
        $_SESSION['username'] = $username;
        $_SESSION['password'] = $password;
        header("location: messageh.php");
    }
    else{
        echo <<<STR
        <script type="text/javascript">
            alert("用户名或密码错误，请重新输入！")
            window.location.href = 'loginpage.html';
        </script>
        STR;
        exit;
     }
    ?>
</body>
</html>

2.注册页面

前端 .html

DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>注册页面title>
head>
<script>  
//二次确认密码是否输入正确
    function checkpassword()
    {  
            if(password.value != repassword.value)
            {  
                alert("两次输入密码不一致！请重新输入密码！")
                repassword.value = "";  
            }
    }
    //检验不能为空
function checkempty() {
    $user_username = document.getElementById("username").value;
    $user_password = document.getElementById("repassword").value;
    // $user_sex = document.getElementById("sex").value;
    $user_grade = document.getElementById("grade").value;
    $user_cls = document.getElementById("cls").value;
    $user_QQ = document.getElementById("QQ").value;
    if ($user_username == '' || $user_username.length < 2 || $user_username.length > 12) {
        alert("用户名不能为空且用户名长度是2---12位哦");
        username.value = "";
        return;
    }
    if ($user_password == '') {
        alert("密码不能为空");
        return;
    }
    if ($user_grade == '') {
        alert("年级不能为空");
        return;
       
    }
    if ($user_cls == '') {
        alert("班级不能为空");
        return;
    }
    if ($user_QQ == '' || $user_QQ.length < 5 || $user_QQ.length > 10) {
        alert("QQ为5到10位数字且不能为空");
        QQ.value = "";
        return;
       
    }
    var form=document.getElementById('form');
    form.submit();
}
script>
<body>
    <form method="POST" action="register.php" id="form" enctype="multipart/form-data">
    用户名：<input type="text" name="username" id="username"  placeholder="请输入用户名"><br>
	密   码：<input type="password" name="password" id="password" placeholder="请输入密码"><br>
    确认密码：<input type="password" id="repassword" onblur="checkpassword()" placeholder="请再次输入密码"><br>
    性别:<label for="nan">男label><input type="radio" name="sex" value="男" id="nan">
         <label for="nv">女label><input type="radio" name="sex" value="女" id="nv">
         <label for="renyao">人妖label><input type="radio" name="sex" value="人妖" id="renyao"><br>
         
         <tr>
            <th style="text-align:right;"><label for="grade">年级：label>th>
            <td>
            <select name="grade" id="grade" >
            <option value="">请选择你的年级option>
            <option value="2022级">2022级option>
            <option value="2021级">2021级option>
            <option value="2020级">2020级option>
            <option value="2019级">2019级option>
            <option value="2018级">2018级option>
            <option value="2017级">2017级option>
            <option value="2016级">2016级option>
            <option value="2015级">2015级option>
            select>
            td>
        tr><br>
        
        <tr>
            <th style="text-align:right;"><label for="cls">班级：label>th>
            <td>
            <select name="cls" id="cls" >
            <option value="">请选择你的班级option>
            <option value="22计科">22计科option>
            <option value="22软工安全1班">22软工安全1班option>
            <option value="22软工安全2班">22软工安全2班option>
            <option value="22软工数据库1班">22软工数据库1班option>
            <option value="22软工数据库2班">22软工数据库2班option>
            <option value="22软工移动1班">22软工移动1班option>
            <option value="22软工移动2班">22软工移动2班option>
            <option value="22软工移动3班">22软工移动3班option>
            <option value="22软工云计算1班">22软工云计算1班option>
            <option value="22软工云计算2班">22软工云计算2班option>
            <option value="22软工云计算3班">22软工云计算3班option>
            <option value="22软工云计算4班">22软工云计算4班option>
            <option value="22软工云计算5班">22软工云计算5班option>
            <option value="22软工智能1班">22软工智能1班option>
            <option value="22软工智能3班">22软工智能2班option>
            <option value="22软工智能2班">22软工智能3班option>
            <option value="22软工智能4班">22软工智能4班option>
            <option value="22软工智能5班">22软工智能5班option>
            <option value="22软工智能6班">22软工智能6班option>
            <option value="22软工智能7班">22软工智能7班option>
            <option value="22大数据">22大数据option>
            <option value="22人工智能">22人工智能option>
            <option value="22网络空间安全">22网络空间安全option>
            select>
            td>
        tr><br>
        
        QQ:<input type="text" name="QQ" id="QQ" placeholder="请输入QQ(5到10位)"/><br>
        <p>
	<input type="button" value="注册" onclick="checkempty()"><p>
    <a href="loginpage.html" target="_self">返回a>
    form>
body>
html>

后端 .php

<!DOCTYPE html>
<html lang='en'>
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>注册页面</title>
    </head>
    <body>
    <?php
    $username = $_POST['username'];
    $password = $_POST['password'];
    $sex = $_POST['sex'];
    $grade = $_POST['grade'];
    $cls = $_POST['cls'];
    $QQ = $_POST['QQ'];
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from admin where username='$username'";
    $result = mysqli_query($link,$sql);
if($result->num_rows>0)//如果数据库内存在相同用户名，则'$result'接收到的变量为'true'所以大于1为真，则返回'用户名已存在'
{
    echo "用户名已存在，请重新注册！";
    echo "[返回]";
} 
else //否则可以成功注册递交
{
    $sql = "insert into admin(username,password,sex,grade,cls,QQ) values('{$username}','${password}','${sex}','${grade}','${cls}','${QQ}')";
    $result = mysqli_query($link,$sql) or die('信息读取失败');
    if (!$result) 
    {
        printf("Error: %s\n", mysqli_error($link));
        exit();
    }
$sql="select username,password from admin where username='$username'";
$result = mysqli_query($link,$sql) or die('信息读取失败');
$a = mysqli_fetch_array($result);
if($a['username']==$username && $username!='')
{
    echo <<<STR
    <script type="text/javascript">
        alert('注册成功！');
        window.location.href = 'loginpage.html';
    </script>
    STR;
//     echo "注册成功,三秒后自动跳转至登录页面
";
//     header ("Refresh:3;url=loginpage.html");
//     echo'点击此处立刻跳转';
} 
 else
 {
    echo "注册失败，三秒后请重新注册账号！";
    header ("Refresh:3;url=loginpage.html");
    echo'点击此处立刻跳转';
 }
}
?>
    </body>
</html>

3.留言板页面

.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>留言板</title>
</head>
<body>
    <?php
    session_start();
    $username = $_SESSION['username'];
    $message = $_POST['message'];
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "insert into message(username,messages) values('$username','$message')";
    $result = mysqli_query($link,$sql) or die('信息写入失败');
        if($result==TRUE){
        echo <<<STR
        <script type="text/javascript">
            
            window.location.href = 'messageh.php';
        </script>
        STR; 
    }
    else
    echo <<<STR
    <script type="text/javascript">
        alert('留言失败！');
        window.location.href = 'messageh.php';
    </script>
    STR;
    ?>
</body>
</html>

展示留言 .php

img1.jpg可根据自己喜好更换！

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>留言板</title>
    <!-- <style type="text/css">
        body{
            background-image: url(img1.jpg);
            background-size: cover;
        }
    </style> -->
    <style type="text/css">
        body{
            background-image: url(img1.jpg);
            background-size: cover;
        }
        textarea{
            background:transparent;
            border-style: 80px;
            
        }
        input::-webkit-input-placeholder {
        color: orange;
        font-size: 12px;
        }
    </style>
</head>
<body>
    <a href="loginpage.html" target="_self">切换账号</a><br>
    <form method="POST" action="message.php" align="center">
    <tr>
        <h1>请您留言</h1>
        <!-- <th style="text-align:right;" name="message"><label for="message">请您留言：</label></th><br> -->
        <td><textarea name="message" rows="15" cols="80" placeholder="请输入您的留言"></textarea></td><br>
    </tr>
    <tr>
        <th></th>
        <td><input type="submit" id="submit" value="提交" name="submit"></td><br>
    </tr>
</form>
<table align="center" border="1px" cellspacing="0px" width="800px">
    <tr>
        <th>用户名</th>
        <th>留言</th>
        <th>操作</th>
    </tr>
<?php
 $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
 $sql = "select id,username,messages from message order by id DESC";
 $result = mysqli_query($link,$sql) or die('信息读取失败');
 $did = $_GET['id'];
 if(!empty($did)){
    $sql="delete from message where id ='$did'";
    $result = mysqli_query($link,$sql);
    if($result!=TRUE){
        echo"error";
        exit(0);
    }
    header("location:messageh.php");
 }
 session_start();
 $usr = $_SESSION['username'];
while($row = mysqli_fetch_array($result)){
    
    $username = $row['username'];
    $con = 0;
    if($username == $usr)
    {
        $con = 1 ;
    }
    $id = $row['id'];
    $messages = $row['messages'];
    if($con ==1 )
    {
        echo '';
        echo "'color:#FF0000'>$username'left'>$messages
              
        'messageh.php?id=$id'>'button' align='right' value='删除'> 
              ";
        echo '';
    }
    else {
            echo '';
            echo "$username'left'>$messages";
            echo '';
        }
}
    ?>
</table>
</body>
</html>

4.管理员页面

大家可以看到，虽然都是管理员页面，但只有站主才可以设置管理员，同时，管理员与管理员之间也是不能相互进行管理员操作的！

（1）管理员登录页面

管理员登录页面前端 .html

DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>管理员登录title>
head>
<body>
    <script>
        //用户名和密码不能为空
    function checkform() {
        $user_name = document.getElementById("username").value;
        $user_pwd = document.getElementById("password").value;
        if ($user_name == '') {
            alert("用户名不能为空");
            window.location.href = 'admin.html';
        }
    
        if ($user_pwd == '') {
            alert("密码不能为空");
            window.location.href = 'admin.html';
            // window.history.go(-1);
        }
    }
    script>
    <body>
        <form method="POST" action="admin1.php" align="center">
            <h1>管理员登录h1>
            用户名：<input type="text" name="adminusername" id="username" placeholder="请输入用户名"><br/>
            密　码：<input type="password" name="adminpassword" id="password" placeholder="请输入密码"><br>
            <input type="submit"value="登录" onclick="checkform()">
            <a href="loginpage.html"><input type="button" value='返回主页面'>a>
            form>
            <p>
body>
html>

（2）管理员登录分流

根据的值来进行判断。值为1则认定为站主，进入站主页面；值为0则认定为普通管理员，进入管理员页面。

管理员登录页面后端分流 .php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>管理员页面</title>
</head>
<body>
<?php
    $adminusername = $_POST['adminusername'];
    $adminpassword = $_POST['adminpassword'];
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from manage where adminusername='$adminusername' and adminpassword='$adminpassword'";
    $result = mysqli_query($link,$sql) or die('信息读取失败');
    $a = mysqli_fetch_array($result);
    if($a['adminusername']==$adminusername && $adminusername!='' && $a['adminpassword']==$adminpassword && $adminpassword!='' && $a['wwwhost'] == 1){
        session_start();
        $_SESSION['adminusername'] = $adminusername;
        $_SESSION['adminpassword'] = $adminpassword;
        header("location: wwwhost.php");
    }
    else if($a['adminusername']==$adminusername && $adminusername!='' && $a['adminpassword']==$adminpassword && $adminpassword!=''){
        session_start();
        $_SESSION['adminusername'] = $adminusername;
        $_SESSION['adminpassword'] = $adminpassword;
        header("location: admin.php");
    }
    else{
        echo <<<STR
        <script type="text/javascript">
            alert('非管理员不能登录！！！');
            window.location.href = 'admin.html';
        </script>
        STR;
        }
    ?>
</body>
</html>

ⅰ管理员页面

管理员页面 .php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>管理员</title>
</head>
<body>
    <a href="loginpage.html" target="_self">注销登录</a><br>
    <h1 align="center">管理员页面</h1>
    <form method="POST" action="">
    <p align="center"><input type="text" name="search" /><input type="submit" value="搜索" name="find"/></p><!-- search为第一个输入的文本框,find为搜索按钮 -->
    <p align="center"><a href="admin.php"><input type="button" value='显示全部'></a></p>
    <p>
    <p align="center"><a href="loginpage.php"><input type="button" value='返回主页面'></a></p>
    <p align="center"><a href="deletemessage.php"><input type="button" value="查看全部留言"></a></p>
    </form>
    <table align="center" border="1px" cellspacing="0px" width="800px">
    <tr>
        <th>id</th>
        <th>用户名</th>
        <th>密码</th>
        <th>性别</th>
        <th>年级</th>
        <th>班级</th>
        <th>QQ</th>
        <th>管理员操作</th>
    </tr>
    <script language='javascript'>  
        function del(a){
            if(/confirm/i('确定要删除吗？')){
                location.href='delete.php?id=' + a;
        // alert('删除成功！');
            }else{
                return;
            }
        }
    </script>
<?php
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from admin order by id DESC";
     if(empty($_POST["find"])){
        $result = mysqli_query($link,$sql);
    }else{
        $search = $_POST["search"];
        $sql = "select * from admin where id like '%$search%' or username like '%$search%' or sex like '%$search%' or grade like '%$search%' or cls like '%$search%' or QQ like '%$search%'";
        $result = mysqli_query($link,$sql);
    }
    while($row = mysqli_fetch_array($result))
    {
        $sqluser = "select count(*) from manage where adminusername = '$row[1]'";
        $resultuser = mysqli_query($link,$sqluser);
        $arryuser = mysqli_fetch_array($resultuser);
        echo '';
        echo "$row[0]$row[1]$row[2]$row[3]$row[4]$row[5]$row[6]
              ";
        if($arryuser['count(*)'] == 0){ 
            echo "'update.php?id=$row[0]'>'submit' value='修改' />
            'button' οnclick='del($row[0])' value='删除该用户' />";
        }
        echo '';
   }  
   mysqli_close($link);
     
?>
    </table>
</body>
</html>

普通管理员删除留言

.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>用户留言</title>
    <!-- <style type="text/css">
        body{
            background-image: url(img1.jpg);
            background-size: cover;
        }
    </style> -->
</head>
<body>
<body>
    <a href="loginpage.html" target="_self">注销登录</a><br>
    <h1 align="center">用户留言</h1>
    <form method="POST" action="">
    <p align="center"><input type="text" name="search" /><input type="submit" value="搜索" name="find"/></p><!-- search为第一个输入的文本框,find为搜索按钮 -->
    <p align="center"><a href="deletemessage.php"><input type="button" value='显示全部'></a></p>
    <p>
    <p align="center"><a href="admin.php"><input type="button" value='返回管理员页面'></a></p>
    </form>
    <table align="center" border="1px" cellspacing="0px" width="800px">
    <tr>
        <th>id</th>
        <th>用户名</th>
        <th>留言</th>
        <th>管理员操作</th>
    </tr>
    <script language='javascript'>  
        function del(a){
            if(/confirm/i('确定要删除该条留言吗？')){
                location.href='delmessage.php?id=' + a;
        // alert('删除成功！');
            }else{
                return;
            }
        }
    </script>
<?php
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from message order by id DESC";
     if(empty($_POST["find"])){
        $result = mysqli_query($link,$sql);
    }else{
        $search = $_POST["search"];
        $sql = "select * from message where id like '%$search%' or username like '%$search%' or messages like '%$search%'";
        $result = mysqli_query($link,$sql);
    }
    while($row = mysqli_fetch_array($result))
    {
        
        if(empty($row)){
            break;
        }
        echo '';
        echo "$row[0]$row[1]'left'>$row[2]
              
              'button' οnclick='del($row[0])' value='删除该留言' />
              ";
        echo '';
        
   }  
   mysqli_close($link);
     
?>
    </table>
</body>
</html>

.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>删除用户留言</title>
</head>
<body>
    <?php
   if(isset($_GET['id']) && !empty($_GET['id'])) {
    $id = $_GET['id'];
} else {
    // 若没有传入id参数，直接跳转到首页
    header('Location:deletemessage.php');
}
// 执行数据库删除操作
$link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
$sql = "delete from message where id = $id";
$result = mysqli_query($link,$sql) or die('信息读取失败');
if($result == true) {
    echo <<<STR
cript type="text/javascript">
    alert("该用户此条留言已删除!")
    window.location.href = 'deletemessage.php';
cript>
STR;
exit;
} else {
    echo <<<STR
cript type="text/javascript">
    alert("该用户此条留言删除失败!")
    windows.location.href = 'deletemessage.php';
cript>
STR;
}
mysqli_close($link);
 ?>
</body>
</html>

普通管理员修改用户信息

.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>修改用户信息</title>
</head>
<script>  
二次确认密码是否输入正确
    function checkpassword()
    {  
            if(password.value != repassword.value)
            {  
                alert("两次输入密码不一致！请重新输入密码！")
                // password.value = "";  
                repassword.value = "";  
            }
    }
//     不能为空
function checkempty() {
    $user_username = document.getElementById("username").value;
    $user_password = document.getElementById("repassword").value;
    // $user_sex = document.getElementById("sex").value;
    $user_grade = document.getElementById("grade").value;
    $user_cls = document.getElementById("cls").value;
    $user_QQ = document.getElementById("QQ").value;
    if ($user_username == '' || $user_username.length < 2 || $user_username.length > 12) {
        alert("用户名不能为空且用户名长度是2---12位哦");
        return;
       
    }
    if ($user_password == '') {
        alert("密码不能为空");
        return;
     
    }
    // if ($user_sex == '') {
    //     alert("性别不能为空");
    //     window.history.go(-1);
    // }
    if ($user_grade == '') {
        alert("年级不能为空");
        return;
       
    }
    if ($user_cls == '') {
        alert("班级不能为空");
        return;
      
    }
    if ($user_QQ == '' || $user_QQ.length < 5 || $user_QQ.length > 10) {
        alert("QQ为5到10位数字且不能为空");
        QQ.value = "";
        return;
       
    }
    document.getElementById('sub').value='1';
    var form=document.getElementById('form');
    form.submit();
}
</script>
<?php
//建立数据库连接
$id = $_GET['id'];
$link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
$sql = "select * from admin where id = $id";
$result = mysqli_query($link,$sql) or die('信息读取失败');
$admin = mysqli_fetch_assoc($result);
mysqli_free_result($result);
//更新留言信息
if(($_POST['sub'])==1) { //  用户已经提交表单
	//获取表单数据
	$username = $_POST['username'];
	$password = $_POST['password'];
	$sex = $_POST['sex'];
	$grade = $_POST['grade'];
	$cls = $_POST['cls'];
	$QQ = $_POST['QQ'];
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from admin where username='$username'";
    $result = mysqli_query($link,$sql);
    if($result->num_rows>0)//如果数据库内存在相同用户名，则'$result'接收到的变量为'true'所以大于1为真，则返回'用户名已存在'
    {
        echo <<<STR
        cript type="text/javascript">
            alert("用户名已存在，请重新修改!")
            window.location.href = 'admin.php';
        cript>
        STR;
        exit;
    } 
    else{
	//执行sql语句
	$sql = "update admin set username = '$username',password = '$password',sex = '$sex',grade = '$grade',cls = '$cls',QQ='$QQ' where id = '$id'";
	if(mysqli_query($link,$sql) && mysqli_affected_rows($link) == 1) {
		echo <<cript type="text/javascript">
	alert('修改成功！');
	window.location.href = 'admin.php';
cript>
STR;
	} else {
		echo mysqli_error($link);
	}
} }
?>
<body>
	<form action="" method="post" id="form">
        
    用户名：<input type="text" name="username" id="username" placeholder="请输入新的用户名"><br>
	密   码：<input type="password" name="password" id="password" placeholder="请输入新的密码"><br>
    确认密码：<input type="password" id="repassword" onblur="checkpassword()" placeholder="请再次输入新的密码"><br>
    性别:<label for="nan">男</label><input type="radio" name="sex" value="男" id="nan">
         <label for="nv">女</label><input type="radio" name="sex" value="女" id="nv">
         <label for="renyao">人妖</label><input type="radio" name="sex" value="人妖" id="renyao"><br>
         
         <tr>
            <th style="text-align:right;"><label for="grade">年级：</label></th>
            <td>
            <select name="grade" id="grade">
            <option value="">请选择你的新年级</option>
            <option value="2022级">2022级</option>
            <option value="2021级">2021级</option>
            <option value="2020级">2020级</option>
            <option value="2019级">2019级</option>
            <option value="2018级">2018级</option>
            <option value="2017级">2017级</option>
            <option value="2016级">2016级</option>
            <option value="2015级">2015级</option>
            </select>
            </td>
        </tr><br>
       	 
        <tr>
            <th style="text-align:right;"><label for="cls">班级：</label></th>
            <td>
            <select name="cls" id="cls">
            <option value="">请选择你的新班级</option>
            <option value="22计科">22计科</option>
            <option value="22软工安全1班">22软工安全1班</option>
            <option value="22软工安全2班">22软工安全2班</option>
            <option value="22软工数据库1班">22软工数据库1班</option>
            <option value="22软工数据库2班">22软工数据库2班</option>
            <option value="22软工移动1班">22软工移动1班</option>
            <option value="22软工移动2班">22软工移动2班</option>
            <option value="22软工移动3班">22软工移动3班</option>
            <option value="22软工云计算1班">22软工云计算1班</option>
            <option value="22软工云计算2班">22软工云计算2班</option>
            <option value="22软工云计算3班">22软工云计算3班</option>
            <option value="22软工云计算4班">22软工云计算4班</option>
            <option value="22软工云计算5班">22软工云计算5班</option>
            <option value="22软工智能1班">22软工智能1班</option>
            <option value="22软工智能3班">22软工智能2班</option>
            <option value="22软工智能2班">22软工智能3班</option>
            <option value="22软工智能4班">22软工智能4班</option>
            <option value="22软工智能5班">22软工智能5班</option>
            <option value="22软工智能6班">22软工智能6班</option>
            <option value="22软工智能7班">22软工智能7班</option>
            <option value="22大数据">22大数据</option>
            <option value="22人工智能">22人工智能</option>
            <option value="22网络空间安全">22网络空间安全</option>
            </select>
            </td>
        </tr><br>
         
        QQ:<input type="text" name="QQ" id="QQ" placeholder="请输入新的QQ"><br>
        <input type="hidden" name="sub" value="0" id="sub">
		<p><input type="button" value="更新" onclick="checkempty()" />
        <a href="admin.php" target="_self">返回</a></p> 
	</form>
</body>
</html>

ⅱ站主页面

站主页面 .php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>站主页面</title>
    <!-- <style type="text/css">
        body{
            background-image: url(img1.jpg);
            background-size: cover;
        }
    </style> -->
</head>
<body>
    <a href="loginpage.html" target="_self">注销登录</a><br>
    <h1 align="center">管理员总页面</h1>
    <form method="POST" action="">
    <p align="center"><input type="text" name="search" /><input type="submit" value="搜索" name="find"/></p><!-- search为第一个输入的文本框,find为搜索按钮 -->
    <p align="center"><a href="wwwhost.php"><input type="button" value='显示全部'></a></p>
    <p>
    <p align="center"><a href="loginpage.php"><input type="button" value='返回主页面'></a></p>
    <p align="center"><a href="hostdeletemessage.php"><input type="button" value="查看全部留言"></a></p>
    </form>
    <table align="center" border="1px" cellspacing="0px" width="800px">
    <tr>
        <th>id</th>
        <th>用户名</th>
        <th>密码</th>
        <th>性别</th>
        <th>年级</th>
        <th>班级</th>
        <th>QQ</th>
        <th>管理员操作</th>
    </tr>
    <script language='javascript'>  
        function del(a){
            if(/confirm/i('确定要删除吗？')){
                location.href='delete.php?id=' + a;
        // alert('删除成功！');
            }else{
                return;
            }
        }
        function set(a){
            if(/confirm/i('确定进行管理员更改操作？')){
                location.href='setmanage.php?id=' + a;
        // alert('设置成功');
            }else{
                return;
            }
        }
    </script>
<?php
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from admin order by id DESC";
     if(empty($_POST["find"])){
        $result = mysqli_query($link,$sql);
    }else{
        $search = $_POST["search"];
        $sql = "select * from admin where id like '%$search%' or username like '%$search%' or sex like '%$search%' or grade like '%$search%' or cls like '%$search%' or QQ like '%$search%'";
        $result = mysqli_query($link,$sql);
    }
    while($row = mysqli_fetch_array($result))
    {
        $sql1 = "select count(*) from manage where adminusername='$row[1]'";
        $result1 = mysqli_query($link,$sql1);
        $arry1 = mysqli_fetch_array($result1);
        $wheremanage = "设置为管理员";
        if($arry1['count(*)'] != 0){
            $wheremanage = "取消管理员" ;
        }
        echo '';
        echo "$row[0]$row[1]$row[2]$row[3]$row[4]$row[5]$row[6]
              
              'hostupdate.php?id=$row[0]'>'submit' value='修改' />
              'button' οnclick='del($row[0])' value='删除该用户' />
              'button' οnclick='set($row[0])' value='$wheremanage' />
              ";
        echo '';
   }  
   mysqli_close($link);
     
?>
    </table>
</body>
</html>

站主删除留言 .php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>用户留言</title>
    <!-- <style type="text/css">
        body{
            background-image: url(img1.jpg);
            background-size: cover;
        }
    </style> -->
</head>
<body>
<body>
    <a href="loginpage.html" target="_self">注销登录</a><br>
    <h1 align="center">用户留言</h1>
    <form method="POST" action="">
    <p align="center"><input type="text" name="search" /><input type="submit" value="搜索" name="find"/></p><!-- search为第一个输入的文本框,find为搜索按钮 -->
    <p align="center"><a href="hostdeletemessage.php"><input type="button" value='显示全部'></a></p>
    <p>
    <p align="center"><a href="wwwhost.php"><input type="button" value='返回管理员页面'></a></p>
    </form>
    <table align="center" border="1px" cellspacing="0px" width="800px">
    <tr>
        <th>id</th>
        <th>用户名</th>
        <th>留言</th>
        <th>管理员操作</th>
    </tr>
    <script language='javascript'>  
        function del(a){
            if(/confirm/i('确定要删除该条留言吗？')){
                location.href='hostdelmessage.php?id=' + a;
        // alert('删除成功！');
            }else{
                return;
            }
        }
    </script>
<?php
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from message order by id DESC";
     if(empty($_POST["find"])){
        $result = mysqli_query($link,$sql);
    }else{
        $search = $_POST["search"];
        $sql = "select * from message where id like '%$search%' or username like '%$search%' or messages like '%$search%'";
        $result = mysqli_query($link,$sql);
    }
    while($row = mysqli_fetch_array($result))
    {
        
        if(empty($row)){
            break;
        }
        echo '';
        echo "$row[0]$row[1]'left'>$row[2]
              
              'button' οnclick='del($row[0])' value='删除该留言' />
              ";
        echo '';
        
   }  
   mysqli_close($link);
     
?>
    </table>
</body>
</html>

.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>删除用户留言</title>
</head>
<body>
    <?php
   if(isset($_GET['id']) && !empty($_GET['id'])) {
    $id = $_GET['id'];
} else {
    // 若没有传入id参数，直接跳转到首页
    header('Location:deletemessage.php');
}
// 执行数据库删除操作
$link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
$sql = "delete from message where id = $id";
$result = mysqli_query($link,$sql) or die('信息读取失败');
if($result == true) {
    echo <<<STR
cript type="text/javascript">
    alert("该用户此条留言已删除!")
    window.location.href = 'hostdeletemessage.php';
cript>
STR;
exit;
} else {
    echo <<<STR
cript type="text/javascript">
    alert("该用户此条留言删除失败!")
    windows.location.href = 'hostdeletemessage.php';
cript>
STR;
}
mysqli_close($link);
 ?>
</body>
</html>

站主修改用户信息 .php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>修改用户信息</title>
</head>
<script>  
二次确认密码是否输入正确
    function checkpassword()
    {  
            if(password.value != repassword.value)
            {  
                alert("两次输入密码不一致！请重新输入密码！")
                password.value = "";  
                repassword.value = "";  
            }
    }
//     不能为空
function checkempty() {
    $user_username = document.getElementById("username").value;
    $user_password = document.getElementById("repassword").value;
    // $user_sex = document.getElementById("sex").value;
    $user_grade = document.getElementById("grade").value;
    $user_cls = document.getElementById("cls").value;
    $user_QQ = document.getElementById("QQ").value;
    if ($user_username == '' || $user_username.length < 2 || $user_username.length > 12) {
        alert("用户名不能为空且用户名长度是2---12位哦");
        return;
       
    }
    if ($user_password == '') {
        alert("密码不能为空");
        return;
     
    }
    // if ($user_sex == '') {
    //     alert("用户名不能为空");
    //     window.history.go(-1);
    // }
    if ($user_grade == '') {
        alert("年级不能为空");
        return;
       
    }
    if ($user_cls == '') {
        alert("班级不能为空");
        return;
      
    }
    if ($user_QQ == '') {
        alert("QQ不能为空");
        return;
       
    }
    document.getElementById('sub').value='1';
    var form=document.getElementById('form');
    form.submit();
}
</script>
<?php
//建立数据库连接
$id = $_GET['id'];
$link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
$sql = "select * from admin where id = $id";
$result = mysqli_query($link,$sql) or die('信息读取失败');
$admin = mysqli_fetch_assoc($result);
mysqli_free_result($result);
//更新留言信息
if(($_POST['sub'])==1) { //  用户已经提交表单
	//获取表单数据
	$username = $_POST['username'];
	$password = $_POST['password'];
	$sex = $_POST['sex'];
	$grade = $_POST['grade'];
	$cls = $_POST['cls'];
	$QQ = $_POST['QQ'];
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from admin where username='$username'";
    $result = mysqli_query($link,$sql);
    if($result->num_rows>0)//如果数据库内存在相同用户名，则'$result'接收到的变量为'true'所以大于1为真，则返回'用户名已存在'
    {
        echo <<<STR
        cript type="text/javascript">
            alert("用户名已存在，请重新修改!")
            window.location.href = 'wwwhost.php';
        cript>
        STR;
        exit;
        // echo "用户名已存在，请重新注册！";
        // header("location: admin.php");
        // //echo "[返回]";
    } 
    else{
	//执行sql语句
	$sql = "update admin set username = '$username',password = '$password',sex = '$sex',grade = '$grade',cls = '$cls',QQ='$QQ' where id = '$id'";
	if(mysqli_query($link,$sql) && mysqli_affected_rows($link) == 1) {
		echo <<cript type="text/javascript">
	alert('修改成功！');
	window.location.href = 'wwwhost.php';
cript>
STR;
	} else {
		echo mysqli_error($link);
	}
} }
?>
<body>
	<form action="" method="post" id="form">
        
    用户名：<input type="text" name="username" id="username" placeholder="请输入新的用户名"><br>
	密   码：<input type="password" name="password" id="password" placeholder="请输入新的密码"><br>
    确认密码：<input type="password" id="repassword" onblur="checkpassword()" placeholder="请再次输入新的密码"><br>
    性别:<label for="nan">男</label><input type="radio" name="sex" value="男" id="nan">
         <label for="nv">女</label><input type="radio" name="sex" value="女" id="nv">
         <label for="renyao">人妖</label><input type="radio" name="sex" value="人妖" id="renyao"><br>
         
         <tr>
            <th style="text-align:right;"><label for="grade">年级：</label></th>
            <td>
            <select name="grade" id="grade">
            <option value="">请选择你的新年级</option>
            <option value="2022级">2022级</option>
            <option value="2021级">2021级</option>
            <option value="2020级">2020级</option>
            <option value="2019级">2019级</option>
            <option value="2018级">2018级</option>
            <option value="2017级">2017级</option>
            <option value="2016级">2016级</option>
            <option value="2015级">2015级</option>
            </select>
            </td>
        </tr><br>
       	 
        <tr>
            <th style="text-align:right;"><label for="cls">班级：</label></th>
            <td>
            <select name="cls" id="cls">
            <option value="">请选择你的新班级</option>
            <option value="22计科">22计科</option>
            <option value="22软工安全1班">22软工安全1班</option>
            <option value="22软工安全2班">22软工安全2班</option>
            <option value="22软工数据库1班">22软工数据库1班</option>
            <option value="22软工数据库2班">22软工数据库2班</option>
            <option value="22软工移动1班">22软工移动1班</option>
            <option value="22软工移动2班">22软工移动2班</option>
            <option value="22软工移动3班">22软工移动3班</option>
            <option value="22软工云计算1班">22软工云计算1班</option>
            <option value="22软工云计算2班">22软工云计算2班</option>
            <option value="22软工云计算3班">22软工云计算3班</option>
            <option value="22软工云计算4班">22软工云计算4班</option>
            <option value="22软工云计算5班">22软工云计算5班</option>
            <option value="22软工智能1班">22软工智能1班</option>
            <option value="22软工智能3班">22软工智能2班</option>
            <option value="22软工智能2班">22软工智能3班</option>
            <option value="22软工智能4班">22软工智能4班</option>
            <option value="22软工智能5班">22软工智能5班</option>
            <option value="22软工智能6班">22软工智能6班</option>
            <option value="22软工智能7班">22软工智能7班</option>
            <option value="22大数据">22大数据</option>
            <option value="22人工智能">22人工智能</option>
            <option value="22网络空间安全">22网络空间安全</option>
            </select>
            </td>
        </tr><br>
         
        QQ:<input type="text" name="QQ" id="QQ" placeholder="请输入新的QQ"><br>
        <input type="hidden" name="sub" value="0" id="sub">
		<p><input type="button" value="更新" onclick="checkempty()" />
        <a href="wwwhost.php" target="_self">返回</a></p> 
	</form>
</body>
</html>

站主设置管理员 .php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>设置管理员</title>
</head>
<body>
    <?php
    if(isset($_GET['id']) && !empty($_GET['id'])) {
        $id = $_GET['id'];
    } else {
        // 若没有传入id参数，直接跳转到首页
        header('Location:wwwhost.php');
    }
    // 执行数据库删除操作
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    $sql = "select * from admin where id = $id";
    $result = mysqli_query($link,$sql) or die('信息读取失败');
    $arr = mysqli_fetch_array($result);
 
    $sql1 = "select count(*) from manage where adminusername='$arr[1]'";
    $result1 = mysqli_query($link,$sql1) or die('信息读取失败');
    $arr1 = mysqli_fetch_array($result1);
    if($arr1['count(*)'] == 0){
        $sql1 = "insert into manage(adminusername,adminpassword) values('$arr[username]','$arr[password]')";
        $result1 = mysqli_query($link,$sql1) or die('信息读取失败');
    }else if($arr1['count(*)'] == 1){
        $sql1 = "delete from manage where adminusername = '$arr[username]'";
        $result1 = mysqli_query($link,$sql1) or die('信息读取失败');
    }
   
    if($result1 == true) {
        echo <<<STR
    <script type="text/javascript">
        alert("管理员修改成功!")
        window.location.href = 'wwwhost.php';
    </script>
    STR;
    exit;
    }else{           
        echo <<<STR
    <script type="text/javascript">
        alert("管理员修改失败!")
        windows.location.href = 'wwwhost.php';
    </script>
    STR;
    }
    mysqli_close($link);
    ?>
</body>
</html>

ⅲ删除用户

删除用户所有信息 .php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>删除用户信息</title>
</head>
<body>
    <?php
    if(isset($_GET['id']) && !empty($_GET['id'])) {
        $id = $_GET['id'];
    } else {
        // 若没有传入id参数，直接跳转到首页
        header('Location:admin.php');
    }
    // 执行数据库删除操作
    $link = mysqli_connect("localhost","root","2356789mmm","liuyanban") or die("错误，未连接到数据库");
    // $sql = "delete from admin where id = $id;";
    // $result = mysqli_query($link,$sql) or die('信息读取失败');
    $sql = "select username from admin where id = $id";
    $result = mysqli_query($link,$sql);
    $arry = mysqli_fetch_array($result);
    $username = $arry['username'];
    $sql_0 = "delete from admin where username = '$username'";
    $sql_1 = "delete from message where username = '$username'";
    $sql_2 = "delete from manage where adminusername = '$username';";
    $result_0 = mysqli_query($link,$sql_0) or die(mysqli_error($link));
    $result_1 = mysqli_query($link,$sql_1) or die(mysqli_error($link));
    $result_2 = mysqli_query($link,$sql_2) or die(mysqli_error($link));
    // $address = 'admin.php';
    session_start();
    $adminusername = $_SESSION['adminusername'];
    $sql1 = "select wwwhost from manage where adminusername = '$adminusername'";
    $result1 = mysqli_query($link,$sql1);
    $arry1 = mysqli_fetch_array($result1);
    if($arry1['wwwhost'] == 1)//判断是否为站主,站主为1
    {
        $address = 'wwwhost.php';   
   
    if($result1 == true) {
        echo <<<STR
    <script type="text/javascript">
        alert("用户信息已删除!")
        window.location.href = '$address';
    </script>
    STR;
    exit;
    } else {           
        echo <<<STR
    <script type="text/javascript">
        alert("用户信息删除失败!")
        windows.location.href = '$address';
    </script>
    STR;
    } 
    }
    else{
        $address = 'admin.php';
        if($result1 == true) {
            echo <<<STR
        <script type="text/javascript">
            alert("用户信息已删除!")
            window.location.href = '$address';
        </script>
        STR;
        exit;
        } else {           
            echo <<<STR
        <script type="text/javascript">
            alert("用户信息删除失败!")
            windows.location.href = '$address';
        </script>
        STR;
        } 
    }
    mysqli_close($link);
    ?>
</body>
</html>

总结

提示：这里对文章进行总结：

笔者也是一初来乍到的小白，文章中不可避免的会出现错误，若网友对笔者的文章有持疑，欢迎大家在评论区讨论，至此，关于留言板的设计与实现已经完成，谢谢大家的点击！