javascript实现下拉菜单的显示与隐藏

demo.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>实现下拉菜单效果</title>
    <link rel="stylesheet" type="text/css" href="demo.css">
    <script type="text/javascript" src="demo.js"></script>
</head>
<body>
<div id="nav">
    <ul>
        <li><a href="#">首页</a></li>
        <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)"><a href="#">课程大厅</a>
            <ul>
                <li><a href="#">JavaScript</a></li>
                <li><a href="#">Html/CSS</a></li>
            </ul>
        </li>
        <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)"><a href="#">学习中心</a>
            <ul>
                <li><a href="#">视频学习</a></li>
                <li><a href="#">实例练习</a></li>
                <li><a href="#">问与答</a></li>
            </ul>

        </li>
        <li><a href="#">经典案例</a></li>
        <li><a href="#">关于我们</a></li>

    </ul>

</div>
</body>
</html>

　　demo.js

function displaySubMenu(li) {

    var subMenu = li.getElementsByTagName("ul")[0];

    subMenu.style.display = "block";

}

function hideSubMenu(li) {

    var subMenu = li.getElementsByTagName("ul")[0];

    subMenu.style.display = "none";

}

　　demo.css

*{ margin:0px; padding:0px;}
body{ font-family:Verdana, Geneva, sans-serif; font-size:14px;}
#nav{ width:600px; height:40px; background-color:#eee; margin:0 auto;}
ul{ list-style:none;}
ul li{ float:left; line-height:40px; text-align:center; width:100px;}

a{ text-decoration:none; color:#000; display:block;}
a:hover{ color:#F00; background-color:#666;}



ul li ul li{ float:none;background-color:#eee; margin:2px 0px;}

ul li ul{ display:none;}

　　效果：

 

2017-09-0 6   2017-09-06   

posted @ 2017-09-06 12:44  1点  阅读(15248)  评论(0)  编辑  收藏  举报