php - 如何在表单验证中使用数据库数据？

Question

您好，我有一个使用数据库进行验证的表单，现在验证仅适用于最新的数据库数据，我应该如何验证每个数据。

数据库信息

demo-form.php

<form name="login1" action="demo-login.php" onsubmit="return validateForm1()" method="post" id="form1">
<p>user name: <input type="text" name="luser" id="luser"/></p>
<p>password: <input type="password" name="lpass" id="lpass" /></p>
<input type="submit" value="login" name="submit"/>
</form>

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "users";

$conn2 = new mysqli($servername, $username, $password, $dbname);

if ($conn2->connect_error) {
     die("Connection failed: " . $conn2->connect_error);
} 


$sql2 = "SELECT * FROM users";
$result2 = $conn2->query($sql2);

if ($result2->num_rows > 0) {

     while($row = $result2->fetch_assoc()) {
         $luser = $row["user"];
         $lpass = $row["pass"];
     }
} else {
echo "err_2";
}

$conn2->close();
?> 

<script>
function validateForm1(){
var luser = document.getElementById("luser").value;
var lpass = document.getElementById("lpass").value;
        if (luser == "" || lpass == ""){
            document.getElementById("luser").placeholder="Fill, it's necessary";
            document.getElementById("lpass").placeholder="Fill, it's necessary";
            return false;
        }
        if (luser !== "<?php echo $luser; ?>" || lpass !== "<?php echo $lpass; ?>"){
            alert("user or pass is not true");
            return false;
        }
}
</script>

Answer 1

您似乎多次使用 ID“luser”和“lpass”。您不能多次分配标记 ID。改用类并选择这些类。

参见 getElementsByClassName