ZHANGREN 
- $(window).scroll(function() {
- var wScroll = $(this).scrollTop();
- if (wScroll > 200) {
- $('.main .header_lunbo .top_item').addClass('xiding');
- $('.main .right_kefu .right_list:last-child').fadeIn(500)
- } else {
- $('.main .header_lunbo .top_item').removeClass('xiding');
- $('.main .right_kefu .right_list:last-child').fadeOut(500)
- }
- });
- $(".main .right_kefu .right_list:last-child").click(function() {
- $('body,html').animate({
- scrollTop: 0
- },
- 500);
- return false;
- });
html部分和css部分就不写了，没有意思
