日期:2014-05-18  浏览次数:20944 次

网页下拉菜单被掩盖问题?
做了一天了,快疯了,当鼠标移到药品采购计划时,菜单就消失了。
代码是
HTML code

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>JavaScript下拉菜单</title>
    <style type="text/css">
        * {
            padding:0; 
            margin:0;
        }
        body {
            font-family:verdana, sans-serif; 
            font-size:small;
        }
        #navigation, #navigation li ul {
            list-style-type:none;
        }
        #navigation {
            margin:20px;
        }
        #navigation li {
            float:left;
            text-align:center;
            position:relative;
        }
        #navigation li a:link, #navigation li a:visited {
            display:block; 
            text-decoration:none; 
            color:white; 
            width:120px; 
            height:25px; 
            line-height:25px;
            border:1px solid #fff; 
            border-width:1px 1px 0 0; 
            background:#94964A; 
            padding-left:10px; 
        }
        #navigation li a:hover {
            text-decoration:underline;
            color:yellow;
            background:#E97D19; 
        }
        #navigation li ul li a:link,#navigation li ul li a:visited{
            color:white;
            width:180px; 
            height:25px; 
        }
        #navigation li ul li a:hover {
            text-decoration:underline;
            color:yellow;
            background:#E97D19;
        }
        #navigation li ul {
            display:none;
            position:absolute; 
            top:25px;
            left:0;
            margin-top:1px;
        }
    </style>
    <script type="text/javascript">
        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";
        }
    </script>
</head>
<body>
<div style="left:54px; position:absolute; top:71px; height: 60px; width: 700px;">
    <ul id="navigation">
        <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
            <a href="#">信息查询</a>    
            <ul>
                <li><a href="#">药品信息</a></li>
                <li><a href="#">药品采购计划</a></li>
                <li><a href="#">采购员</a></li>
                <li><a href="#">供应商</a></li>
                <li><a href="#">库管员</a></li>
            </ul>
        </li>
        <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
            <a href="#">栏目2</a>    
            <ul>
                <li><a href="#">栏目2->菜单1</a></li>
                <li><a href="#">栏目2->菜单2</a></li>
                <li><a href="#">栏目2->菜单3</a></li>
                <li><a href="#">栏目2->菜单4</a></li>
                <li><a href="#">栏目2->菜单5</a></li>
            </ul>
        </li>
        <li onmouseover="displaySubMenu(this)" onmouseout="hideSubM