jquery - 到达时显示一个 Div - Jquery

Question

我在页面下方有一个 div 相当远的部分。我希望通过滚动到达 div 时显示它。当达到 div 时（大约 30% 通过 div）有没有办法让它淡入淡出？

我确实希望这是有道理的：s

感谢您的关注。

Answer 1

这是一种方法。尽管您也可以尝试许多通用的 scrollspy 插件。（但是引导程序对我不起作用，所以我做了这个。）

function scrollfadein(selector, offset, speed)
{
    if (speed == undefined)
    {
        speed = 1500;
    }

    $(selector)

    /* hide elements initially */
    .css('opacity', 0)

    /* each element gets its own callback so it can be removed after it's triggered */
    .each(function(){ 
        var el = $(this);
        var fun = function()
        {
            /* calculate offset if it's a fraction multiply by element height */
            offset = (offset == undefined) ? 0 : (offset < 1 ? offset*el.height() : offset);

            /* height and offset might all change if window is resized, so 
               always use up-todate values. */
            if ( $(window).scrollTop() > el.offset().top - $(window).height() + offset )
            {
                /* fadein element */
                el.animate({'opacity':1}, speed);

                /* remove callback now that it has triggered */
                $(window).off('scroll', fun);
            }
        };
        $(window).on('scroll', fun);
    });
}

示例：http: //jsfiddle.net/eg4HS/