Jquery Post image with ajax

im making a jquery mobile app which uploads an image

i used this code but without ajax you cant capture the echo from server(this one worked perfectly)

<form action="http://tipsnow.altervista.org/upload.php" method="post" enctype="multipart/form-data">
            Title: <input type="text" name="title" id="title" />
            Question Text: <input type="text" name="text" id="text" />
            <input type="hidden" id="idUtente" name="idUtente" value="">
            Select image to upload:
            <input type="file" name="fileToUpload" id="fileToUpload">
            <input type="submit" value="Upload Image" name="submit">
        </form>

so i implemented the ajax post

html

<form action="">
                    Title: <input type="text" name="title" id="title" />
                    Question Text: <input type="text" name="text" id="text" />
                    <input type="hidden" id="idUtente" name="idUtente" value="">
                    Select image to upload:
                    <input type="file" name="fileToUpload" id="fileToUpload">
                    <input type="submit" value="Upload Image" name="submit">
                </form>

jquery

$(document).ready(function () {

            $('form').submit(function () {
                var title = document.getElementById('title').value;
                var idUtente = sessionStorage.getItem('autenticato').toString();
                var text = document.getElementById('text').value;
                var fileToUpload = document.getElementById('fileToUpload').files[0];

                var formData = new FormData();
                formData.append('title', title);
                formData.append('text', text);
                formData.append('idUtente', idUtente);
                formData.append('fileToUpload', fileToUpload);
                $.ajax({
                    url: 'http://tipsnow.altervista.org/upload.php',
                    data: formData,
                    type: 'post',
                    dataType: 'text',
                    contentType: false,
                    enctype: 'multipart/form-data',
                    processData: false,
                    success: function (data) {
                        alert(data);
                        return false;
                    }
                })
            });

php

    <?php
$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);
// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
    $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
    if($check !== false) {
        echo "File is an image - " . $check["mime"] . ".";
        $uploadOk = 1;
    } else {
        echo "File is not an image.";
        $uploadOk = 0;
    }
}
// Check file size
if ($_FILES["fileToUpload"]["size"] > 500000) {
    echo "Sorry, your file is too large.";
    $uploadOk = 0;
}
// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
    echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
    $uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
        echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";
    } else {
        echo "Sorry, there was an error uploading your file.";
    }
}
?>

but as soon as i press the submit button it takes me to the first page off the app without uploading anything,which i think means that the ajax wasnt successfull but whats the problem?

@edit noticed that i didnt append the submit button, did it but still doesnt work

@@ edit : 28 seconds after submitting it goes into success but it doesnt upload the img neither get the echos back in response

@@@edit: request

response