Second $.ajax call stuck the code - ajax

Question

I have an ajax+jquery navigation system with $.ajax, and I`m trying to do a second call to $.ajax to send a contact form infos, but, when I add the second $.ajax all just stop working.
First Call -
function loadPage(url)
{
url=url.replace('#!','');
$('#loading').css('visibility','visible');
$.ajax({
type: "POST",
url: "loader.php",
data: 'page='+url,
dataType: "html",
success: function(msg){
if(parseInt(msg)!=0)
{
$('#conteudo').html(msg);
$('#loading').css('visibility','hidden');
}
}
});
}
Second Call
$("#enviar").click(function() {
var str = $("form").serializeArray();
$.ajax({
type: "POST",
url: "update.php",
data: str,
success: function(mn) {
if(parseInt(mn)!=0)
{
$("#conteudo").html(mn);
$("#enviado").css('visibility','visible');
}
}
return false;
});
#EDIT
Very good! The first ajax is not stucking anymore, but this second is not working as expected.
This is intended to parse $_POST values to a php script and if ok just turn div visible..
How I`m doing that -
<form name="formcontato" id="form">
<fieldset>
<label>Seu nome</label>
<input type="text" name="nome" class="input-block-level">
<label>Email</label>
<input type="email" name="email" placeholder="seu#email.com" class="input-block-level">
<div class="form-actions">
<input type="button" name="enviar" value="Enviar" id="enviar" class="btn btn-baixar" />
</div>
</fieldset>
</form>
This is the form.
$("#enviar").click(function () {
var str = $("#form").serialize();
$.ajax({
type: "POST",
url: "update.php",
data: str,
success: function (mn) {
alert("Ok!");
if (parseInt(mn) != 0) {
$("#conteudo").html(mn);
$("#enviado").css('visibility', 'visible');
}
}
});
return false;
});
This is the js
if($_POST) {
$nome = trim($_POST['nome']);
echo $nome;
}
This is the update.php

Answer 1

In what you posted, the second function does not properly close the $.ajax() function with a }); so it would generate a parse error and none of the code in this block would be available.
Try this where the $.ajax() call is succesfully closed.
$("#enviar").click(function () {
var str = $("form").serializeArray();
$.ajax({
type: "POST",
url: "update.php",
data: str,
success: function (mn) {
if (parseInt(mn) != 0) {
$("#conteudo").html(mn);
$("#enviado").css('visibility', 'visible');
}
}
});
return false;
});
FYI, proper and consistent indentation is essential to spotting these issues.