Submit form with javascript/jquery after php validation - php

Question

Could someone help me with this problem.
I have to submit a form after I checked if the database doesn't contain the inserted email.
PHP code for email control
$email = $_POST['email'];
$sql = "SELECT * FROM sc_user WHERE email='" . $email . "'";
$select = mysql_query($sql);
$row = mysql_num_rows($select);
$conn_object->connection_signout();
if($row > 0)
echo "exist";
else
echo "notexist";
PHP code for inserting new user in database
if (isset($_POST['submit_registration']))
{
$sql = "INSERT INTO sc_user (name, surname, email, password) VALUES ('" . $_POST['user_name'] . "',
'" . $_POST['user_surname'] . "', '" . $_POST['email'] . "', '" . md5($_POST['password']) . "')";
if (mysql_query($sql))
{
$conn_object->connection_signout();
}
header("Location: index.php");
}
Part of the javascript code I have is this.
$(document).ready(function(){
$("#register_form").submit(function(evReg) {
evReg.preventDefault();
//other code...
$.post('../PHP/checkMail.php', {'email' : email}, function(data) {
if(data == 'exist')
{
$('#email_id').val('');
$('#email_id').attr('placeholder', 'User already registered with this email');
$('#email_id').addClass('placeholder_red');
$('#email_id').focus();
}
else
{
$(this).submit();
}
});
//this.submit();
//other code
If I put "this.submit();" outside "$.Post(...);" block the form will submit corectly, but if is inside it's like it doesn't find the form, I think.
Sorry for the english, I hope you will understand my problem.
I've tried using this
document.getElementById("register_form").submit();
but it doesn't work. I hope I give you all the information you ned.

Answer 1

It doesn't work because you are inside the scope of the callback function of $.post() so $(this) doesn't reference properly to your form, you can try changing your code like this:
$("#register_form").submit(function(evReg) {
evReg.preventDefault();
var $this = $(this);
//other code
and then in your callback function submitting the form using the $this variable
if(data == 'exist')
{
$('#email_id').val('');
$('#email_id').attr('placeholder', 'User already registered with this email');
$('#email_id').addClass('placeholder_red');
$('#email_id').focus();
}
else
{
$this.submit();
}
I haven't tested your code, so i cannot be sure it works but different times this worked for me.