Cancel submit jquery - php

Question

This is a part of the code from a form requesting data to check if the email alredy exist. The thing is, the program is supposed to return 0 if there is no any mail like this. It dont work properly, because the program keep sending the data, even if the mail is not correct.
If you want more info, or i am missing something let me know. Thanks in advance.
$(document).ready(function () {
$("#enviar").click(function(e) {
e.preventDefault();
var error = false;
consulta = $("#email2").val();
$.ajax({
type: "POST",
url: "compruebaEmail.php",
data: "b="+consulta,
dataType: "html",
error: function(){
alert("error petición ajax");
},
success: function(data){
if(data==0){
$("#error").html("Email incorrecto");
error = false;
}else{
$("form").unbind('submit').submit();
}
}
});
if (error){
return false;
}
});
});
And here is my compruebaEmail.php
<?php require_once('connections/vinoteca.php'); ?>
<?php
mysql_select_db($database_vinoteca, $vinoteca);
$user = $_POST['b'];
if(!empty($user)) {
comprobar($user);
}
function comprobar($b) {
$sql = mysql_query("SELECT * FROM usuarios WHERE email = '".$b."'");
$contar = mysql_num_rows($sql);
if($contar == 0){
echo 0;
}else{
echo 1;
}
}
?>
And here goes the POST
<form method="POST" name="form1" action="validarUsu.php">
<div class="row">
<span class="center">Email</span>
</div>
<div class="row">
<input type="text" name="email" id="email2" value="" size="32" />
</div>
<div class="row">
<span class="center">Contraseña</span>
</div>
<div class="row">
<input type="password" name="password" id="id2" value="" size="32" />
</div>
<div class="row">
<span id="error"> </span>
</div>
<div class="row">
<input type="submit" value="Acceder" id="enviar" size="20">
</div>
<div class="row">
Recuperar contraseña
</div>
</form>

Answer 1

The problem is you're returning false from your Ajax function. You need to return false from your click function. Give this a try:
$("#enviar").click(function() {
var error = false;
consulta = $("#email2").val();
$.ajax({
type: "POST",
url: "compruebaEmail.php",
data: "b="+consulta,
dataType: "html",
error: function(){
alert("error petición ajax");
},
success: function(data){
if(data==0){
$("#error").html("Email incorrecto");
error = true;
}
}
});
if (error)
return false;
});

Answer 2

If all you want is canceling the submitting event, then :
Either :
1 - Add the event arg to your click handler :
$("#enviar").click(function(event){
2 - use event.preventDefault(); when you want to cancel the submit message :)
or change the "return false;" location so that it will be triggered in the "click" handler scope and note the "success" scope e.g with a boolean that would represent if there is an error (EDIT : that is Styphon' solution)
Documentation here : http://api.jquery.com/event.preventdefault/