[PHP知识库]PHP登录

前端页面

?

<form class="ui large form" method="post" action="#">
           <div class="ui  segment">
             <div class="field">
               <div class="ui left icon input">
                 <i class="user icon"></i>
                 <input type="text" name="username" placeholder="用户名">
               </div>
             </div>
             <div class="field">
               <div class="ui left icon input">
                 <i class="lock icon"></i>
                 <input type="password" name="password" placeholder="密码">
               </div>
             </div>
             <button class="ui fluid large teal submit button">登   录</button>
           </div>

           <div class="ui error mini message"></div>
           <!--<div class="ui mini negative message" >用户名和密码错误</div>-->

         </form>

后端PHP代码7.3版本

<?php
header('Content-type:text/html;charset=utf-8');
//连接认证
$link = mysqli_connect('localhost:3306','root','123456') or die('连接失败');

//设定字符集
mysqli_query($link,'set names utf8');

//选择数据库
mysqli_query($link,'use myblog');


if (empty($_POST)){
    require ('login.html');
}else{
    $user['username'] = trim($_POST['username']);
    if (empty($user['username'])){
        error('用户名不能为空');
    }
    $user['password'] = trim($_POST['password']);
    if (empty($user['password'])){
        error('密码不能为空');
    }


    $sql ="select user_name,password from user where user_name = '$user[username]' and password = '$user[password]'"; //查询数据库中的用户名和密码 并返回集合
    //$sql = "select * from user where user_name = '$user[username]'and password = '$user[password]'";

    $rs = mysqli_query($link,$sql);

    if (($row = mysqli_fetch_assoc($rs))>0){//取出数据判断是否>0
        header('location: index.html');//链接到后台管理页面
    }else{
        echo '用户名或密码错误';
        }
}

数据库

create table user(
                     id int primary key auto_increment,
                     user_name varchar(10) not null comment '用户名',
                     password varchar(50) not null comment '密码'
)charset utf8;