// 顶部切换 window.onscroll = function () { var topScroll = get_scrollTop_of_body(); //滚动的距离,距离顶部的距离 var am_nav = document.getElementById("am_nav"); //获取到导航栏id if (topScroll > 250) { //当滚动距离大于250px时执行下面的东西 am_nav.style.position = 'fixed'; am_nav.style.top = '0'; am_nav.style.zIndex = '9999'; am_nav.style.maxWidth = '800px'; } else { //当滚动距离小于250的时候执行下面的内容，也就是让导航栏恢复原状 am_nav.style.position = 'static'; } }; function get_scrollTop_of_body() { var scrollTop; if (typeof window.pageYOffset != 'undefined') { //pageYOffset指的是滚动条顶部到网页顶部的距离 scrollTop = window.pageYOffset; } else if (typeof document.compatMode != 'undefined' && document.compatMode != 'BackCompat') { scrollTop = document.documentElement.scrollTop; } else if (typeof document.body != 'undefined') { scrollTop = document.body.scrollTop; } return scrollTop; }; // 帖子切换 function setTabtt(name, cursel, n) { for (i = 1; i <= n; i++) { var menu = document.getElementById(name + i); var con = document.getElementById('con_' + name + '_' + i); menu.className = i == cursel ? 'hover' : ''; con.style.display = i == cursel ? 'block' : 'none'; } }