CSS：.backtoTop2{ ???height: 40px; ???width: 50px; ???position: fixed; ????????padding-top: 8px; ???right: 100px; ???z-index: 9999; ???background: red; ???cursor: pointer; ???text-align: center;}JS：$(document).ready(function(){ ???$(window).scroll( function() { ???????????????????// change scroll event ???????var height = $(window).height(), ?????????//get window height ?????????????top = $(document).scrollTop(); ??????//get scroll top ???????if(top > height ){ ???????????????????????????????????//more than height to show ???????????$("#backToTop2").fadeIn(300).css({ ???????????????top: height-80 ???????????}); ???????} ???????if(top < height ){ ??????????????????????????????????//less than height to disappear ???????????$("#backToTop2").fadeOut(200); ???????} ???}); ???/*back to top click*/ ???$(‘#backToTop2‘).click(function(){ ???????$(‘html, body‘).animate({ ????????????????????// Animation effects --> move ???????????scrollTop: 0 ???????}, 500); ???});}); ?HTML:<divid="backToTop2"class="backtoTop2"></div>
JS 回到顶端 back ?to ?top
原文地址：http://www.cnblogs.com/zwcai/p/7619816.html