1、在页面（HTML）<body></body>里加上A标签（返回顶部超链接）
<a href="#0" class="cd-top">Top</a>
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2、添加css样式（可以写在页面里，也可以写在单独的css样式表里）
.cd-top {
display: inline-block;
height: 40px;
width: 40px;
position: fixed;
bottom: 40px;
right: 10px;
box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
/* image replacement properties */
overflow: hidden;
text-indent: 100%;
white-space: nowrap;
background: rgba(232, 98, 86, 0.8) url(../images/cd-top-arrow.svg) no-repeat center 50%;
visibility: hidden;
opacity: 0;
-webkit-transition: all 0.3s;
-moz-transition: all 0.3s;
transition: all 0.3s;
}
.cd-top.cd-is-visible {
/* the button becomes visible */
visibility: visible;
opacity: 1;
}
.cd-top.cd-fade-out {
/* 如果用户继续向下滚动,这个按钮的透明度会变得更低 */
opacity: .5;
}
.no-touch .cd-top:hover {
background-color: #e86256;
opacity: 1;
}
@media only screen and (min-width: 768px) {
.cd-top {
right: 20px;
bottom: 20px;
}
}
@media only screen and (min-width: 1024px) {
.cd-top {
height: 60px;
width: 60px;
right: 30px;
bottom: 30px;
}
}登录后复制
3、加入js代码（加入js前，一定要先引用jquery库，否则会失效）
<script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
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$(document).ready(function($){
// browser window scroll (in pixels) after which the "back to top" link is shown
var offset = 300,
//browser window scroll (in pixels) after which the "back to top" link opacity is reduced
offset_opacity = 1200,
//duration of the top scrolling animation (in ms)
scroll_top_duration = 700,
//grab the "back to top" link
$back_to_top = $('.cd-top');
//hide or show the "back to top" link
$(window).scroll(function(){
( $(this).scrollTop() > offset ) ? $back_to_top.addClass('cd-is-visible') : $back_to_top.removeClass('cd-is-visible cd-fade-out');
if( $(this).scrollTop() > offset_opacity ) {
$back_to_top.addClass('cd-fade-out');
}
});
//www.sucaijiayuan.com
//smooth scroll to top
$back_to_top.on('click', function(event){
event.preventDefault();
$('body,html').animate({
scrollTop: 0 ,
}, scroll_top_duration
);
});
});登录后复制
以上就是使用JQUERY实现可变透明度返回顶部效果的详细内容，更多请关注Work网其它相关文章！