Receiving multiple data through AJAX in PHP?

Question

I am working on a login form, where user types in his email, which is validated through AJAX and after that the password is verified through AJAX as well. Here is the code, JS code-

//AJAX for email input field
function emailCheck(email) {
    return $.ajax({
        type: "POST",
        url: "ajax_index.php",
        data: "email=" + email
    });
}

//AJAX for password input field
function passwordCheck(password, email) {
    return $.ajax({
        type: "POST",
        url: "ajax_index.php",
        data: {password: password, email: email}
    });
}

PHP code -

//receives POST request from email field
if (isset($_POST['email'])) {
    $email = mysqli_real_escape_string($dbconn, $_POST['email']);

    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        echo -1;
    } else {
        $query = "SELECT * from users WHERE email = '$email'";
        $query_result = mysqli_query($dbconn, $query) or die(mysqli_error($dbconn));
        $result_rows = mysqli_num_rows($query_result);

        echo $result_rows;
    }
}

//receives POST from password field
if (isset($_POST['password'], $_POST['email'])) {
    $email = mysqli_real_escape_string($dbconn, $_POST['email']);
    $password = mysqli_real_escape_string($dbconn, $_POST['password']);

    $query = "SELECT email, password from users WHERE email = '$email'";
    $query_result = mysqli_query($dbconn, $query) or die(mysqli_error($dbconn));
    $result_rows = mysqli_num_rows($query_result);

    $row = mysqli_fetch_assoc($query_result);

    if (password_verify($password, $row['password'])) {
        echo 1;
    }
    else {
        echo 0;
    }
}

As you can see, for the password field, I have to get both the $_POST['password'] and $_POST['email'] , so that I can verify the password against that email. But this invokes both handlers, the one for only email field and the one for both email and password which the one I only want to run. So, how I can solve this problem? Thank you.

Answer 1

So, silly problem, I just had to put the handler for password field inside the handler for email field in a conditional block. So it works if I change to this -

if (isset($_POST['email'])) {
    if(isset($_POST['password'])) {
        $email = mysqli_real_escape_string($dbconn, $_POST['email']);
        $password = mysqli_real_escape_string($dbconn, $_POST['password']);

        $query = "SELECT email, password from users WHERE email = '$email'";
        $query_result = mysqli_query($dbconn, $query) or die(mysqli_error($dbconn));
        $result_rows = mysqli_num_rows($query_result);

        $row = mysqli_fetch_assoc($query_result);

        if (password_verify($password, $row['password'])) {
            echo 1;
        }
        else {
            echo 0;
        }
    }
    else {
        $email = mysqli_real_escape_string($dbconn, $_POST['email']);

        if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            echo -1;
        } else {
            $query = "SELECT * from users WHERE email = '$email'";
            $query_result = mysqli_query($dbconn, $query) or die(mysqli_error($dbconn));
            $result_rows = mysqli_num_rows($query_result);

            echo $result_rows;
        }
    }
}

Or as Sasikumar said, using an extra variable will work as well.