Ajax PHP - Check returned response/data value from php

Question

Basically, I am validating a sign-up form and calling a php script with ajax to check if an email address already exists or else the query executes. If an email address already exists (checked with a count query), I am echoing an error back to the ajax function (via response) - however it is not being read.

I tried researching similar topics but no luck.

ajax

$.ajax({
                type: 'POST',
                url: 'signup-user.php',
                dataType: 'text',
                data: $('form').serialize(),
                success: function(response) {

                        if(response == "error-email-exists"){
                            $('#errorMsg').html("An account is already assosciated with the email adress you entered.");
                            $('#errorMsg').hide().stop(true,true).fadeIn(600);
                        }else if(response == "success"){
                            window.location = "index.php";
                        }else{
                            $('#errorMsg').html(response);
                            $('#errorMsg').hide().stop(true,true).fadeIn(600);
                        }


                }
            });

php

<?php
    session_start(); 
    include("conn.php");

    $post_firstName = $_POST['firstName'];
    $post_lastName = $_POST['lastName'];
    $post_dateofBirth = $_POST['dateofBirth'];
    $post_gender = $_POST['gender'];
    $post_propertyNo = $_POST['propertyNo'];
    $post_propertyAddress = $_POST['propertyAddress'];
    $post_streetAddress = $_POST['streetAddress'];
    $post_locality = $_POST['locality'];
    $post_email = $_POST['email'];
    $post_password = $_POST['password'];


    $checkexistsQuery = $conn->prepare('SELECT count(*) AS countExists FROM tbl_account acc WHERE acc.email = ?');

    $checkexistsQuery->bind_param('s', $post_email); 
    $checkexistsQuery->execute();

    $checkexistsQuery->store_result();
    $checkexistsQuery->bind_result($countExists);
    $checkexistsQuery->fetch();

    if($countExists > 0){
        echo 'error-email-exists';
    }else{
        $signupQuery = $conn->prepare('insert into tbl_account (name, surname, email, password, dob, genderID, propertyNumber, propertyAddress, streetAddress, localityID) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)');

        $signupQuery->bind_param('ssssssssss', $post_firstName,$post_lastName,$post_dateofBirth,$post_gender,$post_propertyNo,$post_propertyAddress,$post_streetAddress,$post_locality,$post_email,$post_password); 

        if($signupQuery->execute()){
            echo 'success';
        }else{
            echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
        }


    }

?>

The problem is that 'error-email-exists' and 'success' messages are not being read.

Answer 1

Refactor your code as below. Use json type as contentType and add an error method to your ajax. With json you will be more flexible and have the opportunity to add structured data like errors, messages and even markup.

js:

$.ajax({
    type: 'POST',
    url: 'signup-user.php',
    dataType: 'json',
    data: $('form').serialize(),
    success: function (response) {
        if (response.error) {
            $('#errorMsg').html(response.message);
            $('#errorMsg').hide().stop(true, true).fadeIn(600);
        } else {
            if (response.exists) {
                $('#errorMsg').html("An account is already assosciated with the email adress you entered.");
                $('#errorMsg').hide().stop(true, true).fadeIn(600);
            } else {
                window.location = "index.php";
            }
        }
    },
    error: function (error) {
        console.log(error);
    }
});

php:

<?php
    session_start(); 
    include("conn.php");

    $post_firstName = $_POST['firstName'];
    $post_lastName = $_POST['lastName'];
    $post_dateofBirth = $_POST['dateofBirth'];
    $post_gender = $_POST['gender'];
    $post_propertyNo = $_POST['propertyNo'];
    $post_propertyAddress = $_POST['propertyAddress'];
    $post_streetAddress = $_POST['streetAddress'];
    $post_locality = $_POST['locality'];
    $post_email = $_POST['email'];
    $post_password = $_POST['password'];


    $checkexistsQuery = $conn->prepare('SELECT count(*) AS countExists FROM tbl_account acc WHERE acc.email = ?');

    $checkexistsQuery->bind_param('s', $post_email); 
    $checkexistsQuery->execute();

    $checkexistsQuery->store_result();
    $checkexistsQuery->bind_result($countExists);
    $checkexistsQuery->fetch();

    $response = [];
    $response['error'] = false;

    if($countExists > 0){
        $response['exists'] = true;
    }else{
        $signupQuery = $conn->prepare('insert into tbl_account (name, surname, email, password, dob, genderID, propertyNumber, propertyAddress, streetAddress, localityID) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)');

        $signupQuery->bind_param('ssssssssss', $post_firstName,$post_lastName,$post_dateofBirth,$post_gender,$post_propertyNo,$post_propertyAddress,$post_streetAddress,$post_locality,$post_email,$post_password); 

        if($signupQuery->execute()){
            $response['exists'] = false;
        }else{
            $response['error'] = true;
            $response['message'] = "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
        }
    }

    echo json_encode($response);
?>