<div id="result_form"></div><br>

<div class="form inline">
    <form id="ajax_form">
        <div class="form_body">
            <div class="form-control">
                <label><span>Животное<span class="star">*</span></span>
                </label>
                <input type="text" class="inputtext" name="pet" maxlength="255" value="">
            </div>

            <div class="form-control">
                <label><span>Имя<span class="star">*</span></span>
                </label>
                <input type="text" class="inputtext" name="name" maxlength="255" value="">
            </div>

            <div class="form-control">
                <label><span>Дата рождения<span class="star">*</span></span>
                </label>
                <input type="text" name="birthdate" onclick="BX.calendar({node: this, field: this, bTime: false});" value="">
            </div>

            <div class="form-control">
                <label><span>Дата вакцинации<span class="star">*</span></span>
                </label>
                <input type="text" name="vakcdate" onclick="BX.calendar({node: this, field: this, bTime: false});" value="">
            </div>

            <div class="form-control">
                <label><span>Дата глистогонности<span class="star">*</span></span>
                </label>
                <input type="text" name="glistdate" onclick="BX.calendar({node: this, field: this, bTime: false});" value="">
            </div>

            <div class="form-control">
                <label><span>Картинка анонса</span>
                </label>
                <input type="file" size="30" name="image" value="">
            </div>

            <div class="clearboth"></div>
        </div>
        <div class="form_footer">
            <button type="submit" class="btn btn-default" value="submit" id="add"><span>Отправить</span></button>
        </div>
    </form>
</div>

<script>

$( document ).ready(function() {
    $("form#ajax_form").submit(function(event){
        //disable the default form submission
        event.preventDefault();

        sendAjaxForm('result_form', 'ajax_form', 'add.php');
        return false;
    });
});

function sendAjaxForm(result_form, ajax_form, url) {
    // Get form
    var form = $("#"+ajax_form)[0];

    // Create an FormData object
    var data = new FormData(form);

    $.ajax({
        url:     url, //url страницы (action_ajax_form.php)
        type:     "POST", //метод отправки
        processData: false,  // Important!
        dataType: "json", //формат данных
        data: data,  // Сеарилизуем объект
        success: function(result) { //Данные отправлены успешно
            $('#result_form').html(result.status + ': ' + result.message);
            if (result.status == "OK") {
                $('#result_form').css('color','green');
            } else {
                $('#result_form').css('color','red');
            }
        },
        error: function(response) { // Данные не отправлены
            $('#result_form').html('Ошибка. Данные не отправлены.');
        }
    });

    console.log(data);
}

</script>