How to get form data to the next page - php

I am trying to check the form on this page and if everything is entered correct I want send the $name, $sport, $beoefenaar and $text to the page http://localhost/051R4-verwerk.php. But the variables aren't being sent to that page.
<!DOCTYPE HTML>
<html>
<head>
<title>Inzendopdracht 051R4</title>
<meta charset="utf-8" />
<link rel="stylesheet" href="style.css" type="text/css" media="all" />
</head>
<body>
<a href='viewguestbook.php'>View Guestbook</a>
<?php
// define variables and set to empty values
$nameErr = $sportErr = $beoefenaarErr = $textErr = "";
$name = $sport = $beoefenaar = $text ="";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$valid = true;
if (empty($_POST["name"])) {
$nameErr = "Name is required";
$valid = false;
} else {
$name = test_input($_POST["name"]);
}
if (empty($_POST["sport"])) {
$sportErr = "Sport is required";
$valid = false;
} else {
$sport = test_input($_POST["sport"]);
}
if (empty($_POST["text"])) {
$textErr = "Comment is required";
$valid = false;
} else {
$text = test_input($_POST["text"]);
}
if (empty($_POST["beoefenaar"])) {
$beoefenaarErr = "Comment is required";
} else {
$beoefenaar = test_input($_POST["beoefenaar"]);
}
if($valid){
header("location: http://localhost/051R4-verwerk.php");
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>Laat hier u bericht achter</h2>
<p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
Sport: <select name="sport">
<option valeu="">
<option valeu="Tennis">Tennis
<option valeu="Voetbal">Voetbal
<option valeu="Running">Running
<option valeu="Tafeltenis">Tafeltenis
<option valeu="Squash">Squash
<option valeu="Wielrennen">Wielrennen
<option valeu="Boksen">Boksen
</select>
<span class="error">* <?php echo $sportErr;?></span>
<br><br>
Beoefenaar:
<INPUT TYPE="radio" name="beoefenaar" value="0" checked>Nee
<INPUT TYPE="radio" name="beoefenaar" value="1">Ja
<br><br>
<textarea name="text" placeholder="Schrijf hier u bericht*" /></textarea>
<span class="error"> <?php echo $textErr;?></span>
<br><br>
<input type="submit" value="Verstuur"/>
</form>
</body>
</html>

The issue is that you aren't including your second PHP file. You are redirecting to the second PHP file. This means that your are instructing the browser to load up a new page with a new HTTP request. PHP can't store variables between calls, so when this new request comes in all previous variables (and history) are lost. Each page executes completely separate from every other page.
Instead, the simplest way to accomplish what you are trying to accomplish is with sessions. This allows you to store information on a user between script executions. PHP will automatically create cookies for you and manage the session information. You just have to get your data into the session, and then get it back out of the session in your second script. In your first script that could look something like this:
if($valid){
$_SESSION['name'] = $name;
$_SESSION['sport'] = $sport;
/// and more
header("location: http://localhost/051R4-verwerk.php");
}
Then in your receiving script:
$name = isset( $_SESSION['name'] ) ? $_SESSION['name'] : '';
$sport = isset( $_SESSION['sport'] ) ? $_SESSION['sport'] : '';
This will only work if the two scripts are hosted by the same server and on the same domain. There are lots of tutorials out there about using sessions. You will actually still have to validate the data again in your second script, because a user can go directly to it without any information in the session.
Your second option would be to include the second script instead of redirecting to it, in which case your variables will actually be available, but you will also have to adjust the way your first page works. Maybe something like:
if($valid){
include "051R4-verwerk.php";
exit;
}

Related

PHP form with multiple steps and validation

I'm new to PHP and I'm trying to create an easy form that has multiple steps. For each step, a validation of the input is happening before the user is directed to the next page. If the validation fails, the user should stay on the same page and an error message should be displayed. In the end, all entries that the user has made should be displayed in an overview page.
What I have been doing to solve this, is to use a boolean for each page and only once this is true, the user can go to the next page. This is not working as expected unfortunately and I guess it has something to do with sessions in PHP... I also guess that there's a nicer way to do this. I would appreciate some help!
Here's my code:
<!DOCTYPE HTML>
<html>
<head>
<title>PHP Test</title>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<?php
session_start();
$_SESSION['$entryOne'] = "";
$_SESSION['$entryOneErr'] = $_SESSION['$emptyFieldErr'] = "";
$_SESSION['entryOneIsValid'] = false;
$_SESSION['$entryTwo'] = "";
$_SESSION['$entryTwoErr'] = "";
$_SESSION['entryTwoIsValid'] = false;
// Validation for first page
if ($_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['submitEntryOne'])) {
if (!empty($_POST["entryOne"])) {
// Check for special characters
$_SESSION['$entryOne'] = removeWhitespaces($_POST["entryOne"]);
$_SESSION['$entryOneErr'] = testForIllegalCharError($_SESSION['$entryOne'], $_SESSION['$entryOneErr']);
// If error text is empty set first page to valid
if(empty($_SESSION['$entryOneErr'])){
$_SESSION['$entryOneIsValid'] = true;
}
} else {
// Show error if field hasn't been filled
$_SESSION['$emptyFieldErr'] = "Please enter something!";
}
// Validation for second page
} else if ($_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['submitEntryTwo'])) {
if (!empty($_POST["entryTwo"])) {
// Check for special characters
$_SESSION['$entryTwo'] = removeWhitespaces($_POST["entryTwo"]);
$_SESSION['$entryTwoErr'] = testForIllegalCharError($_SESSION['$entryTwo'], $_SESSION['$entryTwoErr']);
// If error text is empty set second page to valid
if(empty($_SESSION['$entryTwoErr'])){
$_SESSION['$entryTwoIsValid'] = true;
}
} else {
// Show error if field hasn't been filled
$_SESSION['$emptyFieldErr'] = "Please enter something!";
}
}
//Remove whitespaces at beginning and end of an entry
function removeWhitespaces($data) {
$data = trim($data);
return $data;
}
//Check that no special characters were entered. If so, set error
function testForIllegalCharError($wish, $error){
$illegalChar = '/[\'\/~`\!##\$%\^&\*\(\)_\-\+=\{\}\[\]\|;:"\<\>,\.\?\\\]/';
if (preg_match($illegalChar,$wish)) {
$error = "Special characters are not allowed";
} else {
$error = "";
}
return $error;
}
?>
<?php if (isset($_POST['submitEntryOne']) && $_SESSION['$entryOneIsValid'] && !$_SESSION['$entryTwoIsValid']): ?>
<h2>Second page</h2>
<p>Entry from first Page: <?php echo $_SESSION['$entryOne'];?></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Entry Two: <input type="text" name="entryTwo" value="<?php echo $_SESSION['$entryTwo'];?>">
<span class="error"><?php echo $_SESSION['$entryTwoErr'];?></span>
<br><br>
<input type="submit" name="submitEntryTwo" value="Next">
</form>
<?php elseif (isset($_POST['submitEntryTwo']) && $_SESSION['$entryTwoIsValid']): ?>
<h2>Overview</h2>
<p>First entry: <?php echo $_SESSION['$entryOne'];?></p>
<p>Second Entry: <?php echo $_SESSION['$entryTwo'];?></p>
<?php else: ?>
<h2>First page</h2>
<span class="error"><?php echo $_SESSION['$emptyFieldErr'];?></span>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<br><br>
First entry: <input type="text" name="entryOne" value="<?php echo $_SESSION['$entryOne'];?>">
<span class="error"> <?php echo $_SESSION['$entryOneErr'];?></span>
<br><br>
<input type="submit" name="submitEntryOne" value="Next">
</form>
<?php endif; ?>
</body>
</html>
You are setting your session variables to "" at the top of your script.
Check if your variable is set before setting to blank.
Check if Session Variable is Set First
<?php
//If variable is set, use it. Otherwise, set to null.
// This will carry the variable session to session.
$entryOne = isset($_REQUEST['entryOne']) ? $_REQUEST['entryOne'] : null;
if($entryOne) {
doSomething();
}
?>
Tips
Then you can use <?= notation to also echo the variable.
Do this $_SESSION['variable'] instead of $_SESSION['$variable'] (you'll spare yourself some variable mistakes).
<h2>Second page</h2>
<p>Entry from first Page: <?= $entryOne ?></p>
Example Script
This could be dramatically improved, but for a quick pass:
<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
//Check that no special characters were entered. If so, set error
function hasIllegalChar($input){
$illegalChar = '/[\'\/~`\!##\$%\^&\*\(\)_\-\+=\{\}\[\]\|;:"\<\>,\.\?\\\]/';
if (preg_match($illegalChar, $input)) {
return true;
}
return false;
}
session_start();
// Destroy session and redirect if reset form link is pressed.
if(isset($_GET['resetForm']) && $_GET['resetForm'] == "yes")
{
echo "SESSION DESTROY";
session_destroy();
header("Location: ?");
}
// Session
$page = isset($_SESSION['page']) ? $_SESSION['page'] : 1;
$errors = [];
// Value history.
$valueOne = isset($_SESSION['valueOne']) ? $_SESSION['valueOne'] : null;
$valueTwo = isset($_SESSION['valueTwo']) ? $_SESSION['valueTwo'] : null;
// Clean inputs here
$fieldOne = isset($_REQUEST['fieldOne']) ? trim($_REQUEST['fieldOne']) : null;
$fieldTwo = isset($_REQUEST['fieldTwo']) ? trim($_REQUEST['fieldTwo']) : null;
// First form
if ($page == 1) {
// If field two is submitted:
if ($fieldOne) {
//Validate inputs
if(hasIllegalChar($fieldOne)) {
$errors[] = "You entered an invalid character.";
}
if (count($errors) == 0 ){
$valueOne = $_SESSION['valueOne'] = $fieldOne;
$page = $_SESSION['page'] = 2;
}
}
}
// Second form
else if ($page == 2) {
// If field two is submitted:
if ($fieldTwo) {
//Validate inputs
if(hasIllegalChar($fieldTwo)) {
$errors[] = "You entered an invalid character.";
}
if (count($errors) == 0 ){
$valueTwo = $_SESSION['valueTwo'] = $fieldTwo;
$page = $_SESSION['page'] = 3;
}
}
}
?>
<!DOCTYPE HTML>
<html>
<head>
<title>PHP Test</title>
<style>
.error {
color: #FF0000;
}
</style>
</head>
<body>
<?php
// troubleshoot
if (true) {
echo "<pre>";
var_dump($_REQUEST);
var_dump($_SESSION);
echo "</pre>";
}
echo "<h1>Page " . $page . '</h1>';
if (count($errors) > 0) {
$errorMsg = implode('<br/>',$errors);
echo '<div class="error">Some errors occurred:<br/>' . $errorMsg . '</div>';
}
?>
<?php if ($page == 3): ?>
<h2>Overview</h2>
<p>First entry: <?= $valueOne;?></p>
<p>Second Entry: <?= $valueTwo;?></p>
Reset
<?php elseif ($page == 2): ?>
<p>Entry from first Page: <?= $valueOne; ?></p>
<form method="post" action="<?= $_SERVER["PHP_SELF"] ?>">
Entry Two: <input type="text" name="fieldTwo" value="<?= $fieldTwo ?>" autofocus>
<br><br>
<input type="submit">
</form>
<?php else: ?>
<form method="post" action="<?= $_SERVER["PHP_SELF"] ?>">
<br><br>
Entry One: <input type="text" name="fieldOne" value="<?= $fieldOne; ?>" autofocus>
<br><br>
<input type="submit">
</form>
<?php endif; ?>
</body>
<html>
You can run the following command to test out the page without using a fancy tool like WAMP or LAMP.
php -S localhost:8000 index.php
You can now access in the browser at http://localhost:8000.

Using php to display welcome message on the same page using conditional statements

When the user visits the Visitor Log page, they should be able to see a prompt asking them to enter their name. Upon submitting the form, the same page should display a completely different message welcoming the user to the web page. When the user refreshes the page, the process starts over.
This is what I have tried so far, it works, but I still don't understand how I would display a whole new message after the input.
Here is the code I have I need help with only using PHP to have the correct desired result
Attempt
<?php
// define variables and set to empty values
$nameErr = "";
$name = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Name is required";
}
else {
$name = test_input($_POST["name"]);
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$nameErr = "Only letters and white space allowed";
}
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<p2 id="example-id-name" class="centered-text "></p>
<p><span class="error"></span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<input type="text" name="name" value="<?php echo $name;?>">
<span class="error"> <?php echo $nameErr;?></span>
<br> <br>
<input type="submit" name="submit" value="Submit">
</form>
<?php
echo "$name";
echo "<br>";
?>
Where you're echoing name, you can check whether you have it or not and choose the message to display
<?php
if($name) {
echo "Hi $name!\n Welcome to our store!"
}
else {
echo "Please enter your name"
}
echo "<br>";
?>
You can write inline php and functions.
Code:
<?php
# filter input
function filter($var) {
return htmlspecialchars(stripslashes(trim($var)));
}
# validate name
function validate_name(&$name, &$err){
if(empty($name)){
$err = "Name is required";
return;
}
$name = filter($name);
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$err = "Only letters and white space allowed";
}
}
$method = filter_input(INPUT_SERVER, 'REQUEST_METHOD');
$err = "";
# If client post a name, then validate the name
if ($method === "POST"){
$name = $_POST["name"] ?? "";
validate_name($name, $err);
}
?>
<!-- The form -->
<form method="post">
<label>
<input type="text" name="name" value="<?=$name ?? ""; ?>">
</label>
<!-- Show if error -->
<?php if (!empty($err)) { ?>
<span class="error">
<?=$err ?>
</span>
<?php } ?>
<br>
<input type="submit" name="submit" value="Submit">
</form>
<?php if (isset($name) && empty($err)) { ?>
<p>Hi <?=$name ?>!</p>
<p>Welcome to our store!</p>
<?php } ?>

How to $_Post data from submit form PHP after validation

I just saw this codes from this website and thinking to implement it to my project however I cannot get my data on the next page. I am using the test.php as a index and submit.php as a page that will catch the post
here is the codes
test.php
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<?php
// Initialize variables and set to empty strings
$firstName=$lastName="";
$firstNameErr=$lastNameErr="";
// Validate input and sanitize
if ($_SERVER['REQUEST_METHOD']== "POST") {
$valid = true; //Your indicator for your condition, actually it depends on what you need. I am just used to this method.
if (empty($_POST["firstName"])) {
$firstNameErr = "First name is required";
$valid = false; //false
}
else {
$firstName = test_input($_POST["firstName"]);
}
if (empty($_POST["lastName"])) {
$lastNameErr = "Last name is required";
$valid = false;
}
else {
$lastName = test_input($_POST["lastName"]);
}
//if valid then redirect
if($valid){
header('Location: submit.php');
exit();
}
}
// Sanitize data
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>Find Customer</h2>
<p><span class="error">* required</span></p>
<form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']);?>" method="post">
First Name: <input type="text" name="firstName" value="<?php echo $firstName; ?>"><span class="error">* <?php echo $firstNameErr; ?></span><br><br>
Last Name: <input type="text" name="lastName" value="<?php echo $lastName; ?>"><span class="error">* <?php echo $lastNameErr; ?><br><br>
<input type="submit">
</form>
</body>
</html>
submit.php
<?php
$test=$_POST['lastName'];
echo $test;
?>
Your form action should be the file where you want to get the form submitted values .
change this <form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']);?>" method="post"> to <form action="submit.php" method="post">

php validation on submit when jump from one page to another

In this program when i am clicking submit button the page directly goes on other page 2222.php. The error message not pop up.. I just want hit error message when clicking on submit button...
php_validation.php
<?php
// Initialize variables to null.
$nameError ="";
$emailError ="";
$genderError ="";
$name = $email = $gender ="";
// On submitting form below function will execute.
if(isset($_POST['submit']))
{
if (empty($_POST["name"])) //---------------------------------------------- -------------------------
{
$nameError = "Name is required";
}
else
{
$name = test_input($_POST["name"]);
// check name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$name))
{
$nameError = "Only letters and white space allowed";
}
//-----------------------------------------------------------------------
}
if (empty($_POST["email"])) //---------------------------------------------- -------------------------
{
$emailError = "Email is required";
}
else
{
$email = test_input($_POST["email"]);
// check if e-mail address syntax is valid or not
if (!preg_match("/([\w\-]+\#[\w\-]+\.[\w\-]+)/",$email))
{
$emailError = "Invalid email format";
}
}
//-----------------------------------------------------------------------
if (empty($_POST["gender"]))
{
$genderError = "Gender is required";
}
else
{
$gender = test_input($_POST["gender"]);
}
}
function test_input($data)
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP Form Validation Example</h2>
<p><span class="error">* required field.</span></p>
<form method="post" name="myForm" action="2222.php">
<p>First Name:
<input type="text" name="fname" id="fname" />
<span class="error">* <?php echo $nameError;?></span>
</p>
<br><br>
<p>
Email:
<input type="text" name="email" id="email">
<span class="error">* <?php echo $emailError;?></span>
</p>
<br><br>
<p>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<span class="error">*<?php echo $genderError;?></span><br><br />
</p>
<input class="submit" type="submit" name="submit" value="Submit" >
</form>
</body>
2222.php
<?php
$name = $_POST['fname'];
$email = $_POST['email'];
$radio = $_POST['gender'];
echo "<h2>Your Input:</h2>";
echo "user name is: ".$name;
echo "<br>";
echo "user email is: ".$email;
echo "<br>";
echo "user is ".$radio;
?>
So I've done a quick code for you :
Here is your "php_validation.php" :
<?php
//Init error var
$nameError = '';
$emailError = '';
$genderError = '';
//Did we have an error ?
if(isset($_GET['error'])){
//Split error return into an array
$errorList = explode('_', $_GET['error']);
//Verify every possible error
if(in_array('name',$errorList)){
$nameError = 'Please enter your name<br>';
}
if(in_array('email',$errorList)){
$emailError = 'Please enter your email<br>';
}
if(in_array('gender',$errorList)){
$genderError = 'Please enter your gender';
}
}
?>
I didnt changed the form
Then this is your "2222.php" :
<?php
$error ='';
function test_input($data)
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
//When we receive data
if(isset($_POST)){
//Verify all possible data and set error
if(!empty($_POST['fname'])){
$name = test_input($_POST['fname']);
}else{
$error .= 'name_';
}
if(!empty($_POST['email'])){
$email = test_input($_POST['email']);
}else{
$error .= 'email_';
}
if(!empty($_POST['gender'])){
$radio = test_input($_POST['gender']);
}else{
$error .= 'gender_';
}
//if we have an error then redirect to form with error
if(!empty($error)){
header("Location:php_validation.php?error=".$error);
}
}
?>
Didnt changed your output on this page either.
So as I said previously when you here is what happend when you click the submit button :
Submit Click
Form sent to 2222.php as $_POST and you're redirected to this page
There is no way that could be working if your form is posting on an other page than the one where the check is made.
Since your form's action is "2222.php", on click the submit button will automatically redirect you to 2222.php before doing anything.
If you want to check what you've received by your form, you can do it in your "2222.php", then redirect it with the error message to php_validation.php
You could do one of the following things:
Do all the checking in Javascript "onClick" function
Do Ajax call "onClick" to a handler page, get the validation message from that page.
Do the validation on "2222.php" page
action back to the same page (since you are doing some validation here) and redirect after validation on "2222.php" page
Now depends only on you which fits your program.
If you want to stay on the same page you could submit the form to an iframe, as the results of the processing script would be displayed in the iframe itself.
Example:
files:
file-with-form.php
form-submit-processing-file.php
Code examples:
file-with-form.php
<!DOCTYPE html>
<html>
<head>
<title>[Your page title]</title>
</head>
<body>
<h2>PHP Form Validation Example</h2>
<p><span class="error">* required field.</span></p>
<!-- Form -->
<form action="[path-to-form-submit-process]" method="[GET|POST]"
target="form-processor">
<div>
<label>First Name:
<input type="text" name="fname" id="fname" />
<span class="error">* <?php echo $nameError ?></span>
</label>
</div>
<div>
<label>Email:
<input type="text" name="email" id="email">
<span class="error">* <?php echo $emailError ?></span>
</label>
</div>
<div>
<label>Gender:
<p><input type="radio" name="gender" value="female"> Female</p>
<p><input type="radio" name="gender" value="male"> Male</p>
<p><span class="error">*<?php echo $genderError ?></span></p>
</label>
<input class="submit" type="submit" name="submit" value="Submit" >
</div>
</form>
<!-- The iframe to submit the form to -->
<iframe name="form-processor" id="form-processor"
src="[path-to-form-submit-process]"></iframe>
<!--
NOTE: The error message spans are left there just because you had them
in your code, those will not work here at this point, actually depending
on your php configuration will most probably throw errors/warnings,
because such variables were not defined at all...
-->
</body>
</html>
As:
[path-to-form-submit-process] - a placeholder to be replaced with the URL to the file/ Controller -> Action that would process the passed form data
[*] - placeholders that should be replaced with the values for your case
form-submit-processing-file.php
<?php
# Processing the form fields and displaying the messages
$post = $_POST;
# Preprocessing the passed data
// Here you would filter out data from the $_POST superglobal variable
# Validating the passed data
// Check if the data entries, e.g.
// Flag for error risen - does not let the process to be completed
$invalidFormData = false;
$messages = [];
function addErrorMessage($message, &$messages, &$errorFlag)
{
$errorFlag = true;
$errorMessageTemplate = '<p class="error-message">{message}</p>';
array_push($messages, str_replace('{message}', $message,
$errorMessageTemplate));
}
// Validating the email
$email = array_key_exists('email', $post)
? $post['email']
: null;
if (filter_var($email, FILTER_VALIDATE_EMAIL) === false) {
// Raising the flag for an error on validation
addErrorMessage("$email is not a valid email address", $messages, $invalidFormData);
}
// ........
// validation of rest of fields
// ........
$internalError = false;
# Some business logic after the validation, recording more messages etc.
try {
// ........
} catch (Exception $e) {
$internalError = true;
}
# Stop execution on internal error
if ($internalError === true)
{
?>
<h2>Sorry, there's an error on our side... we'll do all in our
powers to fix it right away!</h2>
<?php
exit;
}
# Displaying the results
if ($invalidFormData === true) {
// Building errors message
$messagesHeading = '<h2>There were problems submitting your data. :/</h2>';
} else {
$messagesHeading = '<h2>Your data was successfully submitted! Yay!</h2>';
}
// Placing the heading in front of other messages
array_unshift($messages, $messagesHeading);
// Displaying the messages:
echo implode('', $messages);
However I believe this should be done via an AJAX call insted.
Also there are a lot of bad practices in this case, so I would suggest checking out some design patterns and architectures as MVC for instance and consider using a framework like Symfony/Laravel/CodeIgniter... There are a lot of tools that will make your life easier :)

"Cannot modify header information - headers already sent by" error.How to redirect upon successful submission of the form

My code below uses header for redirection upon successful submission of the form and checks if all error variables are set to NULL for redirecting to another php page.
Please help me out as I have tried many ways but none seems to work for conditional redirection.
<?php
$proName=$proNameErr=$email=$emailErr=$catErr='';
if(isset($_POST["submit"]))
{
if (empty($_POST["proName"])) {
$proNameErr = "Product name is required";
}
else if(!preg_match('/^[a-z0-9 .&]+$/i',$_POST['proName'])){
$proNameErr = "Invalid product Name";
}
else{
$proName = test_input($_POST["proName"]);
}
if($_POST['cat']==0)
{
$catErr="please select an option";
}
else
{
$cat=$_POST['cat'];
}
if (empty($_POST["email"])) {
$email = "";
}
else{
$email = test_input($_POST["email"]);
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email format";
}
}
if($proNameErr=='' && $emailErr=='' && $catErr=='')
{
header("Location: addMedia.php", true, 302);
die();
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<!DOCTYPE html>
<html>
<body>
<h1>ADD Product</h1>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>" method="post" autocomplete="on">
Product Name: <input type="text" name="proName" placeholder="Product Name" maxlength="35" size="40" required value="<?php echo $proName?>">*
<span class="error"><?php echo $proNameErr;?></span><br><br>
Category: <select name="cat" id="cat" size="1" required>
<option value=0>Select...</option>
<option value=1>John</option>
<option value=2>Paul</option>
<option value=3>Ringo</option>
<option value=4>George</option>
<option value=5>ram</option>
<option value=6>rahim</option>
</select>*<span class="error"><?php echo $catErr;?></span><br><br>
Email Address: <input type="email" name="email" value="<?php echo $email?>"> <span class="error"><?php echo $emailErr;?></span><br><br>
<input type="submit" value="submit" name="submit">
</form>
You must have outputted something to the browser before header call. It cannot be exact copy of your code that you show us. Check:
is there any html before php opening tag
is there any whitespace before php opening tag
is another php script included with echo before that script
is the coding utf8 with BOM?
Those are possible reasons of your error.
Output buffering is your friend in this case.
At the top of each page ( or at the very least, the page in question here ) add
ob_start();
/* the rest of the code */
/*and at the end*/
ob_end_flush();

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