php文件
<?php
//定义一个空数组
$UserPasswordArray = [];
//数据库link
$link = @mysqli_connect('localhost','root','root','php_test');
header('content-type:text/html;charset=utf-8');
//用户名
$usernameOriginal = $_POST['username'];//获取username
$name = mb_strimwidth($usernameOriginal,0,12);//限制username的长度
$username = mysqli_real_escape_string($link,$name);//防止username sql注入
//密码
$userpasswordOriginal = $_POST['userpassword'];//获取password
$userpassword = mysqli_real_escape_string($link,$userpasswordOriginal);//防止password sql注入
//编码
mysqli_set_charset($link,'utf8');//连接数据库的编码格式
//sql语句
$SelectSqlTest = "SELECT * FROM `test` WHERE `name`='$username' AND `password`='$userpassword'";//查询test里面的name和password
$SqlAdd = "INSERT INTO `test` (`name`,`password`) value ('$username','$userpassword')";
//判断是否连接错误
if (mysqli_connect_errno()){//如果链接失败返回为True
exit(mysqli_connect_errno());//exit（）返回链接错误信息
}
//执行sql语句
$res = mysqli_query($link,$SelectSqlTest);
$SelectTest =mysqli_query($link,'SELECT * FROM `test`');
//结果放进数组中
while ($row = mysqli_fetch_assoc($res)){
$UserPasswordArray[] =$row;
}
//释放内存
mysqli_free_result($res);
echo $UserPasswordArray[0]['name'];
if($UserPasswordArray[0]['name']==$username){
if($UserPasswordArray[0]['password']==$userpassword){
echo '登陆成功';
}else{
echo '密码错误';
}
}else{
/*
if (mysqli_query($link,$SqlAdd)){
echo "新增成功";
echo '<table border="1px"><tr><th>编号</th><th>用户名</th>密码</th></tr>';
while ($row=mysqli_fetch_assoc($SelectTest)){
echo "<tr><td>{$row['id']}</td><td>{$row['name']}</td>{$row['password']}</td></tr>";
}
mysqli_free_result($SelectTest);
echo '</table>';
}else{
echo '添加失败';
}
*/
echo '登陆失败';
}
?>
html文件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Z.</title>
</head>
<body>
<form method="post" action="resulet.php">
用户名:<input type="text" name="username"><br>
密码:<input type="password" name="userpassword"><br>
确认密码:<input type="password" name="userpasswordRE">
<input type="submit" value="提交">
<input type="reset" value="清除">
</form>
</body>
</html>
mysql
CREATE DATABASE `php_test`;
//新建数据库，并使用数据库
USE `php_test`;
CREATE TABLE `test` (
`id` INT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
`name` VARCHAR(6) NOT NULL,
`password` VARCHAR(6) NOT NULL
) charset=utf8;
//新建数据表
INSERT INTO `test` VALUES (1, 'admin', '123456');
//插入数据
