css
.backToTop {
display: none;
background-color: #000;
font-size: 12px;
position: fixed;
right: 10px;
bottom: 100px;
cursor: pointer;
height: 38px;
width: 38px;
display: block;
background: #2f4050;
padding: 9px 8px;
text-align: center;
color: #fff;
border-radius: 50%;
opacity: .5;
}
js
(function() {
var $backToTopTxt = "返回顶部",
$backToTopEle = $('<div class="backToTop"></div>').appendTo($("body"))
.text($backToTopTxt).attr("title", $backToTopTxt).click(function() {
$("html, body").animate({
scrollTop: 0
}, 120);
});
})();