Question

我使用以下html表单登录：

<!DOCTYPE html>   
<!-- This is a html file for logging in to the virtual adviser -->
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 
    <head>
        <meta charset="UTF-8">
        <title> Pet Tracker Login</title>
        <link rel="stylesheet" type="text/css" media='screen' href="css/login.screen.css">
    </head>
    <body>
        <!-- The div that displays the login form-->
        <div class="login">
            <h1><strong>Welcome to the Pet Tracker System</strong></h1>
            <form action="validateLogin.php" method="POST">
            <fieldset>
            <label for="user">Username</label>
            <p><input type="text" required id = "user" name = "Username" value=""></p>
            <label for="pass">Password</label>
            <p><input type="password" required id = "pass" name = "Password" value=""></p>
            <!-- <p><a href="#">Forgot Password?</a></p> -->
            <p><input type="submit" value="Login"></p>
            </fieldset>
            </form>
            <!-- include the  logo with green background -->
            <img src="images/threeDeePawPrint.png" alt="paw Logo" style="width:194px;height:97px" class = "center">
        </div>
    </body>
</html>

但显然这不是发布，因为我在validateLogin.php页面上收到了一个未定义的索引错误：

<?php 
// start the session for this page and create the array to hold error messages
session_start();
$errmsg_arr = array();
$errflag = false;

$username = 'root';
$password = '';
$url = 'localhost';
$database = 'pet_tracker';

/*  Note that above variables are using single quote for string. When they
    get replaced in the connection statement below, single quotes within
    single quotes will fail, therefore, the string argument in $conn= statement
    must be double quotes
*/

try
{
    $conn = new PDO("mysql:host=$url; dbname=$database",$username,$password);       //create PDO object (PHP Data Objects = PDO)
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);                 /*set the attribute that controls the error mode once the database
                                                                                    has been connected to, so that it throws exceptions (PDO switches to
                                                                                    "silent failure" mode after establishing a successful connection) */
    $conn->exec('SET NAMES "utf8"');                                                    /* PDO has a method exec that runs SQL scripts. Configure the character
                                                                                    encoding to UTF-8 for special characters like smart quotes */

}   
catch (PDOException $e)
{
    echo $e;
    $output = 'Unable to connect to the database server.'.                          //the '.' is the concatenation operator for a string
    $e->getMessage();                                                               //the '->' is the equivalent of the dot operator in Java
    include 'error.html.php';
    exit();
}

//get the username and password posted from the login page (index.php)
if(isset($_POST['user'])) echo 'index user has value'.$_POST['user'];
if(isset($_POST['pass'])) echo 'index user has value'.$_POST['pass'];

$user = $_POST['user'];
$pass = $_POST['pass'];


//query the database for the posted data from form
    $result = $conn->prepare("SELECT * FROM client WHERE username= :un AND password= :pw");
    $result->bindParam(':un', $user);
    $result->bindParam(':pw', $pass);
    $result->execute();
    $rows = $result->fetch(PDO::FETCH_NUM);
    if($rows > 0) 
    {
    $result = $conn->prepare("SELECT * FROM client WHERE username = :un");  //PDO can only handle a row of data at a time?? Cannot select first_name from students, etc.??
    $result->bindParam(':un',$user);
    $result->execute();
    $name = $result->fetchColumn(1);    
    $_SESSION['name'] = $name;
    $_SESSION['user'] = $user;          //the next page employee.php will need the username to get information from the database
    header("location: employee.php");
    }
else{
    $errmsg_arr[] = 'Username and Password are not found';
    $errflag = true;
    }

if($errflag) {
    $_SESSION['ERRMSG_ARR'] = $errmsg_arr;
    session_write_close();
    header("location: index.php");
    exit();
}
?>

我得到的错误在我设置$ user和$ pass变量的行中。我得到的错误是：

注意：未定义的索引：第41行的C：\ xampp \ htdocs \ PetTracker \ validateLogin.php中的用户

注意：未定义索引：在第42行传递C：\ xampp \ htdocs \ PetTracker \ validateLogin.php

Answer 1

$_POST变量的索引应与HTML输入的name属性完全相同。当您尝试将Username作为$_POST['user']访问时，输入字段的名称为user，这是完全错误的。将名称更改为$_POST或将Username索引更改为location

另外考虑检查你的代码，还有很多其他的错误。例如，您需要在Location函数中将header的第一个字母大写为if($_SERVER['REQUEST_METHOD']=='POST'&&isset($_POST['submit'])){ //Your code }else{ //redirect to somewhere else... }。还要考虑在validateLogin.php页面的第一行写下以下条件来检查回发

import mytextfile

print(mytestfile.FOO)

Answer 2

Html从name属性创建输入键。

解决方案1：更改HTML

<input type="text" required id="user" name="user" value="">

或解决方案2：改变PHP

$user = $_POST['Username'];
$pass = $_POST['Password'];

Answer 3

PHP未定义索引的注意事项意味着在数组中找不到数组Key。如果要查看数组的所有元素，可以使用print_r（$ _ POST）;

要解决您的问题，只需将$ _POST ['user']更改为$ _POST ['Username']和$ _POST ['pass']更改为$ _POST ['密码'];

从HTML表单发布时未定义的索引错误

3 个答案: