操作inview.js触发的时间

Question

我想知道我如何操作inview.js脚本，当它被触发的时刻不是在视口中的第一个像素，而是最后一个元素在输出的时候，而是例如50像素以后或更早。inview.js的脚本是

(function ($) {
function getViewportHeight() {
    var height = window.innerHeight; // Safari, Opera
    var mode = document.compatMode;

    if ( (mode || !$.support.boxModel) ) { // IE, Gecko
        height = (mode == 'CSS1Compat') ?
        document.documentElement.clientHeight : // Standards
        document.body.clientHeight; // Quirks
    }

    return height;
}

$(window).scroll(function () {
    var vpH = getViewportHeight(),
        scrolltop = (document.documentElement.scrollTop ?
            document.documentElement.scrollTop :
            document.body.scrollTop),
        elems = [];

    // naughty, but this is how it knows which elements to check for
    $.each($.cache, function () {
        if (this.events && this.events.inview) {
            elems.push(this.handle.elem);
        }
    });

    if (elems.length) {
        $(elems).each(function () {
            var $el = $(this),
                top = $el.offset().top,
                height = $el.height(),
                inview = $el.data('inview') || false;

            if (scrolltop > (top + height) || scrolltop + vpH < top) {
                if (inview) {
                    $el.data('inview', false);
                    $el.trigger('inview', [ false ]);                        
                }
            } else if (scrolltop < (top + height)) {
                if (!inview) {
                    $el.data('inview', true);
                    $el.trigger('inview', [ true ]);
                }
            }
        });
    }
});

// kick the event to pick up any elements already in view.
// note however, this only works if the plugin is included after the elements are bound to 'inview'
$(function () {
    $(window).scroll();
});
})(jQuery);

所有学分都归here所有

我的尝试是添加一个值来偏移顶部的top = $el.offset().top + 50,，这是可行的！但是如何更改自下而上的值呢？谢谢，泰德

Answer 1

我推荐使用http://imakewebthings.com/jquery-waypoints/

你可以这样调用，从底部起10%就能达到你想要的效果：

    $('.flyIn').waypoint(function() {
    $(this).removeClass('hidden');
    $(this).addClass('animated fadeInUp');
    }, { offset: '90%' });