Running PHP in HTML error (This page isn’t working) - php

Question

I setup this signup form for my website. People enter their username, email and password and then it uses php to add it to my database. But I keep getting this error when I run my code. My html file is on my AWS server as well as this PHP file, so I believe there must be an error in my code. I am still very new to PHP.
HTML:
<form method="get" action="signup_form.php">
<input style="width: 300px; display: block; margin-left: auto; margin-right: auto;" type="text" name="signup_name" placeholder="Screen Name">
<br>
<input style="width: 300px; display: block; margin-left: auto; margin-right: auto;" type="text" name="signup_mail" placeholder="Your E-mail">
<br>
<input style="width: 300px; display: block; margin-left: auto; margin-right: auto;" type="password" name="signup_password" id = "password" placeholder="Create Password" required>
<br>
<input style="width: 300px; display: block; margin-left: auto; margin-right: auto;" type="password" name="confirm_password" id = "confirm_password" placeholder="Repeat Password" required>
<br>
<br>
<button onclick="validatePassword()" class="button" style="display: block; margin-left: auto; margin-right: auto;" type="submit" name="submit_login">
SUBMIT
</button>
</form>
and here is my PHP code:
<?php
$signup_name = filter_input(INPUT_GET, 'signup_name');
$signup_mail = filter_input(INPUT_GET, 'signup_mail');
$signup_password = filter_input(INPUT_GET, 'signup_password');
if (!empty($signup_name)){
if (!empty($signup_mail)){
$host = "wildwea.......onaws.com";
$dbusername = "a....in";
$dbpassword = ".Bi....4.";
$dbname = "innodb";
// Create connection
$conn = new mysqli ($host, $dbusername, $dbpassword, $dbname);
if (mysqli_connect_error()){
die('Connect Error ('. mysqli_connect_errno() .') '
. mysqli_connect_error());
}
else{
$sql = "SELECT EXISTS (SELECT 1 FROM Users WHERE Email = $signup_mail);"
if ($sql = 0){
$sql = "INSERT INTO Users (Username, Email, Pword)
values ('$signup_name', '$signup_mail',md5('$signup_password'))";
if ($conn->query($sql)){
echo "New record is inserted sucessfully";
}
else{
echo "Error: ". $sql ."
". $conn->error;
}
$conn->close();
} else {
echo "User already in database";
}
}
}
else{
echo "Password should not be empty";
die();
}
}
else{
echo "Username should not be empty";
die();
}
?>
If you want to see the error here is the link to the sign up page:
http://thewildwear.com/signup.html

Answer 1

We can't see your specific error (looks like there might be multiple) so we won't be able to help you out there. But I could make a suggestion about how to structure your script.
Caveat - this really isn't a good approach for anything but the smallest of applications or for learning.
The main idea is that there is only 1 script and it has processing and display sections. It will only go into the processing section when the form is actually submitted.
If there are any validation errors, it will fall through to the display section and list out the errors and the form.
If there are no validation errors, it will save to the DB and redirect to some other page.
As you develop bigger (and better) applications, you might find that this type of coding will quickly become unwieldy - you're mixing validation, SQL, views/display, etc. all in a single script. They will become more complex and before long you'll have a big ball of spaghetti. Once you hit this point, start looking into frameworks.
But for now, keep on going. Good luck.
<?php
// A list of validation errors. Initialize to an empty list.
$errors = [];
/****************************/
/******** PROCESSING ********/
/****************************/
// The form was submitted
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
// Values submitted from form
$name = $_POST['signup_name'];
$email = $_POST['signup_mail'];
$password = $_POST['signup_password'];
// Validation
if (empty($name)) {
$errors[] = 'Please enter your name';
}
if (empty($email)) {
$errors[] = 'Please enter your email';
}
// ... check if email already exists in your DB.
// ... more validation here
// There are no validation errors, process the form.
if (empty($errors)) {
// At this point, you now have a valid form. Just save it to the DB.
// Redirect to somewhere
}
}
/****************************/
/********** DISPLAY *********/
/****************************/
if (count($errors) > 0) : ?>
<ul>
<?php foreach ($errors as $error): ?>
<li><?php echo $error; ?></li>
<?php endforeach; ?>
</ul>
<?php endif; ?>
<!-- Use "post" and remove action and it will post to itself. -->
<form method="post">
<!-- ... -->