Form validation on IOS not working?

Question

iOS

<form class="form" action="http://meca.kz/sendernext.php" method="post">
    <div class="form-group">
    <label>Оставить заявку на просчет</label>
    <input type="text" name="name" id="name" size="30" required placeholder="Ваше Имя и Телефон" aria-describedby="name-format" required aria-required=”true” pattern=".{6,}"> 
    </div> 
    <button type="submit" class="btn btn-default">Отправить</button>
  </form>

Guys such a question! Why doesn't verification work on IOS devices? What does not only in native safari but also in Google Chrome and in other browsers on IOS Devices