Ajax错误没有错误

Question

I have an ajax script who use jquery and look like that :

$('#myButton').click(function()
    {
        $.ajax({
            url : "sqlScript.php",
            type : 'POST',
            data : '',
            dataType : 'html',
            beforeSend : function(newRequest,opts)    
            {           
                $('#myButton').attr("disabled", "disabled");
            },
            success : function(code_html, statut)
            {
                location.reload();
            },
            error : function(resultat, statut, erreur)
            {
                alert('error')
                location.reload();
            }
        });
    })

And in my sqlScript.php i have nothing like that :

require_once('bdd.php');

$req= $bdd->query("UPDATE ".$table1
                              ." JOIN ".$table2
                              ." ON ".$table1.".".$field1." = ".$table2.".".$field1
                              ." AND ".$table1.".".$field2." = ".$table2.".".$field2
                              ." SET ".$table2.".".$field3." = ".$table2.".".$field3
                           );
echo "OK";

And each time i click on the button with id 'myButton' the ajax launch the script but at the end of the script it don't pass in the success but in the error and i don't don't why. More weird : their is no error, i mean the script finish well and my UPDATE is completly done.

But this UPDATE is really long something like 10 minutes ... so peraphs it's because of that.

======== EDIT ========

In bdd.php i only have the define of my database :

$host = "localhost";
$db_name = "db";
$user = "root";
$password = "";

try
{
   $bdd = new PDO('mysql:host='.$host.';dbname='.$db_name.';charset=latin1', $user, $password);
}
catch (Exception $e)
{
        die('Erreur : ' . $e->getMessage());
}

$table1 = 'table1';
$table2 = 'table2';
$field1 = 'field1';
$field2 = 'field2';
$field3 = 'field3';

Answer 1

It was a problem of timeout just add this line set_time_limit(0); and it's work.