AJAX, PHP form not submitting to database

Question

I've been trying to get this to work for ages, and have read a lot of other answers to similar questions ( How to add AJAX Submit to PHP validation and return message? , ajax submit form why it cannot echo $_POST ) but I just can't seem to get it to work.

Basically what I'm trying to create is a sign-up form that just inserts someone's email address in a new row in a table so I can measure my visitors' conversion rate! Without further ado, here are my scripts, and I sincerely hope you can help me with it :)

HTML Form:

<!-- Signup Form -->
        <form id="signup-form" name="emailform" method="post" action="send_post.php">
            <input type="email" name="email" id="email" placeholder="Email Address" />
            <input type="submit" value="Sign Up" />
        </form> 
<script src="assets/js/main.js"></script>

send_post php:

 <?php
 // Fetching Values From URL
$servername = "*****";
$username = "*****";
$password = "*****";
$dbname = "email";
$email = $_POST['email'];

//Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

//Insert the data

mysqli_query($conn,"INSERT INTO email (email)
VALUES ('$email')");


$conn->close();
?>

Javascript + AJAX:

//Submitting the form
$('#signup-form').submit(function () {
      $.ajax({type: "POST",
              url: "send_post.php",
              data: $("#signup-form"),
              success: function () {
              alert("success");
     }
});
     e.preventDefault(); 
     return false;
});

For the sake of readability I have only included a small portion of the JS code with the ajax bit in it. PS. When I navigate directly to send_post.php it creates an empty row in the database.

Answer 1

There is plenty wrong here, to name a few:

• You are not cancelling the default submit event correctly, e is not defined.
• You are not sending any data, you need to serialize the form and send that, not the form object itself.
• You have an sql injection problem, you should switch to prepared statements and bound placeholders.

Answer 2

您的数据应采用key：value格式才能正确发布

data: {email:$('#email').val()}

Answer 3

I think it's not sufficient to set the request data to the form object:

data: $("#signup-form"),

You need to set the form values explicitly or serialize the form object. See eg Pass entire form as data in jQuery Ajax function for reference.

Answer 4

Try to update your Form-Javascript:

    $('#signup-form').on('submit', function () {
    ...
    data: { email: $('#email').val() }
    ...

So the $_POST['email'] will reach your PHP-Backend as $_POST['email].

Answer 5

Remove the form to make sure the button doesn't refresh the site, when sending normal POST action:

<input type="email" name="email" id="email" placeholder="Email Address" />
<button id="signUpBtn">Sign up</button>
<script src="assets/js/main.js"></script>

send_post.php:

$servername = "*****";
$username = "*****";
$password = "*****";
$dbname = "email";
$email = $_POST['email'];

//Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

//Insert the data

mysqli_query($conn,"INSERT INTO email (email)
VALUES ('$email')");


$conn->close();
?>

Submitting the form:

                        $('#signUpBtn').on("click",function (e) {

                            $.ajax({
                                type: "POST",
                                url: "send_post.php",
                                data: { email: $("#email").val() },
                                success: function () {
                                    alert("success");
                                }
                            });
                            e.preventDefault(); 
                            return false;
                        });

This should do the trick. Make sure to notice the changes I've done in your jQuery part.

Answer 6

There is an answer similar to mine but my php part is much secure so here is the the code.

HTML

<form id="signup-form" name="emailform" >
 <input type="email" name="email" id="email" placeholder="Email Address" />
 <input type="button" id="signup" value="Sign Up" />
</form>

Jquery

$(document).ready(function (){
    $(document).on('click', '#signup', function (){
        $.ajax({
                url: "send_post.php",
                type: "POST",
                data: {
                        "emali": $("#email").val()
                    }
                success: function (response) {
                    alert("response");
                    }
               });
    })
})

PHP

<?php
 // Fetching Values From URL
$servername = "*****";
$username = "*****";
$password = "*****";
$dbname = "email";
$email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);

//Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

//Insert the data
$stmt = $conn -> prepare("INSERT INTO email (email) VALUES (?)");
$stmt -> bind_param('s', $email);

if($stmt -> execute()){
    echo "Done";
}else{
    echo "Not added";
}

$conn->close();
?>