var isscroll = {
    init: function(_el) {
        this.start(_el);
        $(window).on('scroll',
        function() {
            isscroll.start(_el)
        });
    },
    start: function(_el) {
        var self = this;
        $(_el).each(function() {
            var _self = $(this);
            var isscrolltop = $(window).scrolltop();
            var iswindowheiget = $(window).height() * 0.85;
            var _class = $(this).data('animation');
            if (isscrolltop + iswindowheiget > $(this).offset().top) {
                _self.addclass(_class);
            }
        });
    }
}