<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>JS横向延时2级下拉菜单</title> <style> body{ font-size: 12px; color: #333;} body, ul,h2{ margin:0;padding:0;} li { list-style:none;} a{ color: #333; text-decoration: none;} a:hover{ color: #f00;} #nav { width:100%; border:1px solid #000; margin-bottom:10px;} #nav li{ display:inline-block; margin:10px 20px; font-size: 16px; font-weight: bold;} .nav li { float:left; margin: 0 5px; font-size:12px;} .nav { position:absolute; border:1px solid #666; padding: 5px; display:none;} .n1 { left:0;} .n2 { left:80px;} .n3 { left:200px;} </style> </head> <body> <div class="menu"> <ul id="nav"> <li><a href="#">首页</a></li> <li><a href="#">产品中心</a></li> <li><a href="#">关于我们</a></li> </ul> <ul class="nav n1"> <li><a href="#">首页二级菜单1</a></li> <li><a href="#">首页二级菜单2</a></li> <li><a href="#">首页二级菜单3</a></li> </ul> <ul class="nav n2"> <li><a href="#">产品中心二级菜单1</a></li> <li><a href="#">产品中心二级菜单2</a></li> <li><a href="#">产品中心二级菜单3</a></li> <li><a href="#">产品中心二级菜单4</a></li> </ul> <ul class="nav n3"> <li><a href="#">关于我们二级菜单1</a></li> <li><a href="#">关于我们二级菜单2</a></li> </ul> </div> <script> window.onload = function(){ var oUl = document.getElementById('nav'); var aLi = oUl.getElementsByTagName('li'); //获取一级菜单 var aUl = document.getElementsByTagName('ul'); //获取所有ul var timer = null; var that = ''; // 循环遍历所有的一级菜单 for(var i = 0; i < aLi.length; i++){ // 这里加1的原因是第0个li所对应的ul是第1个ul aLi[i].index = i + 1; // 鼠标经过，先关闭定时器，所有2级菜单隐藏，当前2级菜单显示 aLi[i].onmouseover = function(){ clearTimeout(timer); // 这里设置i = 1也是和上面一样，一一对应 for(var i = 1; i< aUl.length; i++){ aUl[i].style.display = 'none'; } aUl[this.index].style.display = 'block'; }; // 鼠标移开时，先延时200毫秒，然后将2级菜单隐藏 aLi[i].onmouseout = function(){ //将当前索引值保存到that变量中 that = this.index; timer = setTimeout(function(){ aUl[that].style.display = 'none'; },200); }; } // 循环遍历所有的二级菜单【原理同上】 for(var i = 1; i < aUl.length; i++){ // 鼠标经过2级菜单，先清空定时器，当前显示 aUl[i].onmouseover = function(){ clearTimeout(timer); this.style.display = 'block'; }; // 鼠标移开2级菜单，延时200毫秒后再隐藏2级菜单 aUl[i].onmouseout = function(){ that = this; timer = setTimeout(function(){ that.style.display = 'none'; },200); } } }; </script> </body> </html>