#ul{
 ....
 z-index: 100;
 }
 #ul li{
 display: inline-block;
 position: relative;
 top: 0;
 left: -25px;
 width: 10%;
 min-width: 70px;
 height: 30px;
 text-align: center;
 line-height: 30px;
 border: 1px solid gray;
 border-radius:10px;
 background-color: aliceblue;
 cursor: pointer;
 -webkit-transition: all ease-in-out 0.3s;
 -moz-transition: all ease-in-out 0.3s;
 -ms-transition: all ease-in-out 0.3s;
 -o-transition: all ease-in-out 0.3s;
 transition: all ease-in-out 0.3s;
 }
 #ul li:hover{background-color: aquamarine;color: red;}
 ...
 .show-hide:hover{background-color: beige}
 .a-div{
 background-color: aquamarine;
 border-radius:10px;
 color: black;
 display: none;
 opacity: 0
 }
 .a{
 z-index: -1;
 display: block;
 ...
 } 

var ul = document.getElementById('ul');
ul.addEventListener('mouseover',listener1,false);
ul.addEventListener('mouseout',listener2,false);
ul.addEventListener('click',listener3,false); 

function listener1(event){
 //event = event||window.event; //兼容IE8及以前版本
 var target = event.target||event.srcElement; //兼容IE8及以前版本
 if(target.tagName.toLowerCase() === 'li'){
 var div1 = target.getElementsByTagName('div')[0];
 div1.style.display = 'block';
 var i = 0;
 var id;
 (function foo(){
 if(i>=1){clearTimeout(id);id=null;return;}
 i+=0.2;
 div1.style.opacity = i;
 id = setTimeout(function(){clearTimeout(id);foo()},30); 　

　　　　})(); 　

　}

 } 

function listener2(event){
 //event = event||window.event;
 var target = event.target||event.srcElement;
 if(target.tagName.toLowerCase() === 'li'){
 var div1 = target.getElementsByTagName('div')[0];
 div1.onmouseover = function(){
 div1.style.display = 'block';
 div1.style.opacity = 1;
 };
 div1.onmouseout = function(){
 div1.style.display = 'none';
 div1.style.opacity = 0;
 };
 div1.style.display = 'none'; //这一组是为了实现当鼠标从上方出去时隐藏div1
 div1.style.opacity = 0;
 }
 } 

var bool = true;
 function listener3(event) {
 var event = event || window.event;
 var target = event.target || event.srcElement;
 if (target.className === 'show-hide') {
 var parent = target.parentElement;
 var adiv = parent.getElementsByClassName('a-div')[0];
 if (window.getComputedStyle(adiv,null).opacity>0.5){bool=false}else{bool=true}
 var height = 90,
 changeH,
 opacity,
 id;
 if (bool) {
 changeH = 0;
 opacity = 0;
 target.innerHTML = '财经 -';
 (function show() {
 if (changeH > height) {clearTimeout(id);return}
 changeH += 5;
 opacity += 0.06;
 //console.log('opacity:'+adiv.style.opacity+',height :'+adiv.style.height);
 adiv.style.height = changeH + 'px';
 adiv.style.opacity = opacity;
 adiv.style.display = 'block';
 id = setTimeout(function () {
　　　　　　　　　　　　　　　　　　　　　clearTimeout(id);
 show();
 }, 16.7);
 })();

 bool = false;
 } else {
 changeH = height;
 opacity = 1;
 target.innerHTML = '财经 +';
 (function hidden() {
 if (changeH < 0) {clearTimeout(id);adiv.style.display = 'none';return}
 changeH -= 10;
 opacity -= 0.11;
 //console.log('opacity:'+adiv.style.opacity+',height :'+adiv.style.height);
 adiv.style.height = changeH + 'px';
 adiv.style.opacity = opacity;
 id = setTimeout(function () {
　　　　　　　　　　　　　　　　　　　　　clearTimeout(id);
 hidden();
 }, 16.7);
 })();
 bool = true;
 }
 }
 }