1
我试图通过使.header的背景向上滑动而不是仅在div“1”的底部触及页面顶部时消失而创建更平滑的过渡并且.header背景从白色变为透明。我试图通过将类.BGupTranisition添加到CSS和jQuery（//上滚 - 否则{）来实现此目的，但这不起作用？有人能指出我在这里做错了吗？ :-)向上滚动基于div位置的向上滚动动画
var lastScrollTop = 0;
$(window).on('scroll', function() {
var header = $('.header');
var stage0 = $('.stage-0');
var scrollTop = $(window).scrollTop();
if (scrollTop > lastScrollTop) {
// down scroll
if (scrollTop > stage0.offset().top + stage0.height()) {
header.addClass('hide');
}
} else {
// up scroll
if (scrollTop <= stage0.offset().top + stage0.height()) {
header.removeClass('headerBGchange headerLIchange');
} else {
header.removeClass('hide').addClass('headerBGchange headerLIchange BGupTranistion');
}
}
lastScrollTop = scrollTop;
});.header {
display: -webkit-box;
display: -webkit-flex;
display: -ms-flexbox;
display: flex;
-webkit-box-align: center;
-webkit-align-items: center;
-ms-flex-align: center;
align-items: center;
height: 80px;
-webkit-transition: top .5s ease;
transition: top .5s ease;
position: fixed;
width: 100%;
top: 0;
background-color: transparent;
overflow: hidden;
}
.header ul {
margin: 20px;
padding: 0;
}
.header ul li {
display: inline-block;
margin-right: 20px;
color: white;
}
.header ul li:last-child {
margin-right: 0;
}
.hide {
top: -80px;
}
.headerBGchange {
Background: white;
}
.BGupTranistion {
<!--slide back up animation-->
}
.header.headerLIchange ul li {
color: Blue;
}
.stage {
color: #fff;
display: -webkit-box;
display: -webkit-flex;
display: -ms-flexbox;
display: flex;
-webkit-box-pack: center;
-webkit-justify-content: center;
-ms-flex-pack: center;
justify-content: center;
-webkit-box-align: center;
-webkit-align-items: center;
-ms-flex-align: center;
align-items: center;
height: 100vh;
background-color: bisque;
font-size: 48px;
\t
}
.stage-0 {
background: black;
}
.stage-1 {
background: #030202;
}
.stage-2 {
background: #060505;
}
.stage-3 {
background: #080707;
}
.stage-4 {
background: #0b0a09;
}
.stage-5 {
background: #0e0c0b;
}
.stage-6 {
background: #110e0e;
}
.stage-7 {
background: #141110;
}
.stage-8 {
background: #161312;
}
.stage-9 {
background: #191515;
}
.stage-10 {
background: #1c1817;
}
.stage-11 {
background: #1f1a19;
}
.stage-12 {
background: #221d1c;
}
.stage-13 {
background: #241f1e;
}
.stage-14 {
background: #272120;
}
.stage-15 {
background: #2a2422;
}
.stage-16 {
background: #2d2625;
}
.stage-17 {
background: #302827;
}
.stage-18 {
background: #322b29;
}
.stage-19 {
background: #352d2c;
}
.stage-20 {
background: #38302e;
}
.stage-21 {
background: #3b3230;
}
.stage-22 {
background: #3e3432;
}
.stage-23 {
background: #413735;
}
.stage-24 {
background: #433937;
}<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<div class="header">
<ul>
<li>Home</li>
<li>About</li>
<li>Contact</li>
</ul>
</div>
<div class="stage stage-0">1</div>
<div class="stage stage-2">3</div>
<div class="stage stage-4">5</div>
<div class="stage stage-6">7</div>
<div class="stage stage-8">9</div>
<div class="stage stage-10">11</div>
<div class="stage stage-12">13</div>
<div class="stage stage-14">15</div>
<div class="stage stage-16">17</div>
<div class="stage stage-18">19</div>
<div class="stage stage-20">21</div>
<div class="stage stage-22">23</div>