Undefined variable in php registration from - php

Question

Continuing from my previous post "PHP and MYSQL database connection and table creation only once", I created the registration form with the PHP code and server side validation. I’m getting some errors as stated below.
i.e. all errors are occurring at the place where i try to print the errors in their respected html class “”. I've made the html "span class" text bold for easy recognition. If their is anything extra solutions for better performance of the form please let me know...
List of errors:
Notice: Undefined variable: error_name in C:\wamp\www\18+\register.php
Notice: Undefined variable: error_username in C:\wamp\www\18+\register.php
Notice: Undefined variable: error_password in C:\wamp\www\18+\register.php
Notice: Undefined variable: error_password2 in C:\wamp\www\18+\register.php
Notice: Undefined variable: error_email in C:\wamp\www\18+\register.php
Register.php
<?php
include ‘database.php';
session_start();
if (isset($_POST['submit'])) {
$error = " "; //Declare a null variable to store error messages
//validation for fullname
if (empty($_POST['fullname'])) {
$error_name = 'Enter Fullname...';
} else {
$fullname = mysql_real_escape_string(trim($_POST['fullname']));
}
//validation for username
if (empty($_POST['username'])){
$error_username = 'Enter Username...';
} else {
$username = mysql_real_escape_string(trim($_POST['username']));
}
//validation for password
if(empty($_POST['password'])){
$error_password = 'Please Enter Your Password...';
} else {
if (empty($_POST['password2'])) {
$error_password2 = 'Re-enter Your Password...';
} else {
if(($_POST['password'])!=($_POST['password2'])){
$error_password2 = 'Passwords Do not match...';
} else {
$confirm = mysql_real_escape_string(md5($_POST['password2']));
}
}
}
//validation for e-mail
if (empty($_POST['email'])) {
$error_email = 'Please Enter your Email ';
} else {
if (preg_match("//custom preg match characters", $_POST['e-mail'])) {
//regular expression for email validation
$email = mysql_real_escape_string($_POST['email']);
} else {
$error_email = 'Your E-mail Address is invalid ';
}
}
if (empty($error)) //send to Database if there's no error '
{
$query= "DB INSERT QUERY";
$result = mysqli_query($dbc, $query);
if (!$result) {
echo 'Failed to Register Your Account...!';
} else {
echo 'Account Registered Successfully...!';
}
}
mysqli_close($sql);//Close the DB Connection
}
?>
Index.php
<form action="register.php" method="post" id="user_registration">
<p id="head">Create Account</p>
<input type="text" id="fullname" name="fullname"/>
**<span class="error" id="fullname"><?php echo $error_name; ?></span>**
<input type="text" id="username" name="username"/>
<span id="availability_status"></span>
**<span class="error" id="username"><?php echo $error_username; ?></span>**
<input type="password" id="password" name="password"/>
**<span class="error" id="password"><?php echo $error_password; ?></span>**
<input type="password" id="password2" name="password2"/>
**<span class="error" id="divCheckPasswordMatch"><?php echo $error_password2;?></span>**
<input type="email" id="email" name="email"/>
**<span class="error" id="email"><?php echo $error_email; ?></span>**
<p class="submit">
<button type="submit"id="submit" name="submit" value="Register”>Register</button>
</p>
</form>

Answer 1

First of all You need to fix the quote at include ‘database.php'; to include 'database.php'; never use curly quote due to this all your code is being blocked.
Next You need to initialize all variable to null or simply ""
OR
You can check if the variable exist or not using isset() like if you want to print value of an variable $val then use this if(isset($val)) echo $val;
UPDATE
You can easily use an array to store errors:
simply use like
$error['name']='Enter Fullname...';
And to check if name error occurs use
if(isset($error['name'])){
//Its an error print error
}

Answer 2

you may need to define these variable on top of the page before using them in code something like this.
$error_name = '';
$error_username = '';
$error_password = '';
$error_password2 = '';
$error_email = '';

Answer 3

Put an else to your if (isset($_POST['submit']))
else { /* What if the user didn't click submit? Else is the answer */
$error_name="";
$error_username="";
$error_password="";
$error_password2="";
$error_email="";
}

Answer 4

The problem is, you are setting the messages only if certain conditions are true. Thus, these variables are not found if those conditions aren't true. To resolve this, use isset() when displaying the errors, e.g.
<?php echo isset($error_name)?$error_name:'' ; ?>
This means check if $error_name is set, if yes display it or display nothing.
Another thing (logically) is that your code is not actually checking for the errors. The $error remains an empty string and you are checking if it is empty which will always be true. You need to either store the errors as arrays or check if all the variables are empty.
Additional:
Can u tell me how to store the errors as arrays..plz
Try this:
<?php
include 'database.php';
session_start();
if (isset($_POST['submit'])) {
$error = array(); //<-- Declare array here
//validation for fullname
if (empty($_POST['fullname'])) {
$error['fullname'] = 'Enter Fullname...'; //<-- adding error into array
} else {
$fullname = mysql_real_escape_string(trim($_POST['fullname']));
}
//validation for username
if (empty($_POST['username'])){
$error['username'] = 'Enter Username...'; //<-- here too and so on..
} else {
$username = mysql_real_escape_string(trim($_POST['username']));
}
//validation for password
if(empty($_POST['password'])){
$error['password'] = 'Please Enter Your Password...';
} else {
if (empty($_POST['password2'])) {
$error['password2'] = 'Re-enter Your Password...';
} else {
if(($_POST['password'])!=($_POST['password2'])){
$error['password2'] = 'Passwords Do not match...';
} else {
$confirm = mysql_real_escape_string(md5($_POST['password2']));
}
}
}
//validation for e-mail
if (empty($_POST['email'])) {
$error['email'] = 'Please Enter your Email ';
} else {
if (preg_match("//custom preg match characters", $_POST['e-mail'])) {
//regular expression for email validation
$email = mysql_real_escape_string($_POST['email']);
} else {
$error['email'] = 'Your E-mail Address is invalid ';
}
}
if (!empty($error)) //send to Database if there's no error '
{
$query= "DB INSERT QUERY";
$result = mysqli_query($dbc, $query);
if (!$result) {
echo 'Failed to Register Your Account...!';
} else {
echo 'Account Registered Successfully...!';
}
}
}
?>
Change your HTML to:
<form action="register.php" method="post" id="user_registration">
<p id="head">Create Account</p>
<input type="text" id="fullname" name="fullname"/>
<!-- checking if error message is set -->
**<span class="error" id="fullname"><?php echo isset($error['fullname'])?$error['fullname']:''; ?></span>**
<input type="text" id="username" name="username"/>
<span id="availability_status"></span>
**<span class="error" id="username"><?php echo isset($error['username'])?$error['username']:''; ?></span>**
<input type="password" id="password" name="password"/>
**<span class="error" id="password"><?php echo isset($error['password'])?$error['password']:''; ?></span>**
<input type="password" id="password2" name="password2"/>
**<span class="error" id="divCheckPasswordMatch"><?php echo isset($error['password2'])?$error['password2']:''; ?></span>**
<input type="email" id="email" name="email"/>
**<span class="error" id="email"><?php echo isset($error['email'])?$error['email']:''; ?></span>**
<p class="submit">
<button type="submit"id="submit" name="submit" value="Register">Register</button>
</p>
</form>
Note:
Please, don't use mysql_* functions in new code. They are no longer maintained and are officially deprecated. See the red box? Learn about prepared statements instead, and use PDO, or MySQLi - this article will help you decide which. If you choose PDO, here is a good tutorial.