$('.subscribe-form').on('click', '.btn-subscribed', function() {
var that = $(this);
if ( validate.. == true ) {
that.fadeOut('slow'); // that.parent().parent().fadeOut();
$('.subscribedSuccess').css('display', 'block');
}
});
<div class="menu">
<div class="content">
</div>
</div>
.content {
// скролл
}