整体代码如下，直接复制即可
<html>
<head>
<title>的实例演示代码</title>
<meta name="generator" content="editplus">
<meta name="author" content="">
<meta name="keywords" content="">
<meta name="description" content="">
<script>
var zhi = '1';
function show_or_none(){
if(zhi =="1"){
document.getelementbyid('div1').style.display="none";
zhi = "2";
}else{
document.getelementbyid('div1').style.display="block";
zhi = "1";
}
}
</script>
</head>
<body>
<div onclick="show_or_none();" style="background:pink;">导航(展开/关闭)</div>
<div id="div1">
<p>首页1</p>
<p>首页2</p>
<p>首页3</p>
</div>
</body>
</html>
