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>
但显然这并没有发布，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C:''examplep''htdocs''PetTracker''validateLogin.php中的user
注意：未定义的索引：在第42行的C:''examplep''htdocs''PetTracker''validateLogin.php中传递
$_POST变量的索引应与HTML输入的name属性完全相同。输入字段的名称是Username，而您正试图将其作为$_POST['user']访问，这是完全错误的。将名称更改为user或将$_POST索引更改为Username
还要考虑一下你的代码，还有很多其他错误。例如，在header函数中，需要将location的第一个字母大写为Location。还可以考虑在validateLogin.php页面的第一行写下以下条件来检查帖子
if($_SERVER['REQUEST_METHOD']=='POST'&&isset($_POST['submit'])){
//Your code
}else{
//redirect to somewhere else...
}
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="">
或者解决方案2：更改PHP
$user = $_POST['Username'];
$pass = $_POST['Password'];
PHP未定义索引的通知意味着在数组中找不到数组键。如果你想查看数组的所有元素，你可以使用print_r（$_POST）；
要解决您的问题，只需将$_POST['user']更改为$_POST['Username]，并将$_POST['pass']更改成$_POSD['Password']