代码出现点buy

 当我鼠标划过学习中心 会出现二级菜单 可是当我划过学习中心, 而二级菜单还没有显示完全, 很快把它在移动到别的链接上然后再移回学习中心。而导致二级菜单显示没有完成使得其菜单卡在那里。。请问这个bug 怎么解决啊

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
    <style type="text/css">
        .top-nav
        {
            font-size: 14px;
            font-weight: bold;
            list-style: none;
        }
        .top-nav li
        {
            float: left;
            margin-right: 1px;
        }
        .top-nav li a
        {
            line-height: 34px;
            text-decoration: none;
            background: #3f240e;
            color: #fff;
            display: block;
            width: 80px;
            text-align: center;
        }       
        .top-nav ul
        {
            list-style: none;
            display: none;
            padding: 0;
            position: absolute;
            height: 0;
            overflow: hidden;
        }
       
        .top-nav li a:hover
        {
            background: url(http://img.mukewang.com/5461b50d0001e28000010034.jpg) 0 0 repeat-x;
        }
        .note
        {
            color: #3f240e;
            display: block;
            background: url(http://img.mukewang.com/5461b50d0001e28000010034.jpg) 0 0 repeat-x;
        }
        .corner
        {
            display: block;
            height: 11px;
            background: url(http://img.mukewang.com/5461b5620001410d00170011.jpg) 31px 0 no-repeat;
        }
    </style>
    <script type="text/javascript">
        window.onload = function () {
       
       //鼠标经过时的效果
            var Lis=document.getElementsByTagName("li") ;  
             for(var i=0;i<Lis.length;++i){  
                 Lis[i].onmouseover = function () {
                    var u = this.getElementsByTagName("ul")[0];
                    if (u != undefined) {
                        u.style.display="block";
                        ChangeH(u.id,1);
                    }
                }
               
               
               
                Lis[i].onmouseleave = function () {
                    var u = this.getElementsByTagName("ul")[0];
                    if (u != undefined) {
                        ChangeH(u.id,-1);
                    }
                }
            }
        }

        function ChangeH(id, count) {
    //    根据ID找到ulList,同时得到其高度
            var ulList = document.getElementById(id);
            var h = ulList.offsetHeight;
   
            h += count;
            if (count > 0) {
                if (h <= 42) {
   // 将高度赋值给ulList,同时,不断调用本函数
                    ulList.style.height = h + "px";
                    setTimeout("ChangeH('" + id + "',1)", 10);
                }
                else {
                    return;
                }
            }
            else {
                if (h > 0) {
  // 将高度赋值给ulList,同时,不断调用本函数
                    ulList.style.height = h + "px";
                    setTimeout("ChangeH('" + id + "',-1)", 10);
                }
                else {
                    ulList.style.display = "none";
                    return;
                }
            }
        }
    </script>
</head>
<body>
    <ul class="top-nav">
        <li><a href="#"><span class="note">慕课网</span></a> </li>
        <li><a href="#">课程大厅</a> </li>
        <li><a href="#">学习中心</a>
            <ul id="mnuUL">
                <span class="corner"></span>
                <li><a href="#">前端课程 </a></li>
                <li><a href="#">手机开发</a> </li>
                <li><a href="#">后台编程</a></li>
            </ul>
        </li>
        <li><a href="#">关于我们</a></li>
    </ul>
</body>
</html>

keida
浏览 1607回答 1
1回答

落寞回头不如华丽转身

产生这个主要原因是因为定时器, 当你移入时, 开启了定时器, 当你移除是, 有开启了一个定时器,  一个增加高度, 一个减少高度, 两者同时运行 ,所以看起来 就是这样的情况 建议  增加一个 timer 变量  ,  移入移除的时候 先清空定时器 ,在从新开启一个定时器 ,既可以解决这个问题, 如不懂 请继续提问
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