JS implémente des effets spéciaux de menu pliant à trois niveaux, et les autres niveaux peuvent automatiquement réduire les compétences

L'exemple de cet article décrit la mise en œuvre d'effets de menu pliable à trois niveaux à l'aide de JS, et les autres niveaux peuvent être automatiquement réduits. Je le partage avec vous pour votre référence. C'est très pratique. Il fonctionne normalement dans IE6, IE7, IE8, FF, Chrome et autres navigateurs. Les détails sont les suivants :
. Conseils : supprimez {height:100px; overflow:auto;} dans #menu ul en CSS pour le rendre hautement adaptatif
Le diagramme d'effet de fonctionnement est le suivant :

Le code d'implémentation est le suivant :

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<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>三级折叠菜单</title>
<style>
*,body,ul,h1,h2{ margin:0; padding:0; list-style:none;}
body{font:12px "宋体"; padding-top:20px;}
a{ color:#777;border:none;}
#menu { width:200px; margin:auto;}
 #menu h1 { font-size:12px; border:#C60 1px solid; margin-top:1px; background-color:#F93;}
 #menu h2 { font-size:12px; border:#E7E7E7 1px solid; border-top-color:#FFF; background-color:#F4F4F4;}
 #menu ul { padding-left:15px; height:100px;border:#E7E7E7 1px solid; border-top:none;overflow:auto;}
 #menu a { display:block; padding:5px 0 3px 10px; text-decoration:none; overflow:hidden;}
 #menu a:hover{ color:#6F0; background:#000;}
 #menu .no {display:none;}
 #menu .h1 a{color:#6F0;}
 #menu .h2 a{color:#06F;}
 #menu h1 a{color:#FFF;}
</style>
<script language="JavaScript">
<!--//
function ShowMenu(obj,n){
 var Nav = obj.parentNode;
 if(!Nav.id){
 var BName = Nav.getElementsByTagName("ul");
 var HName = Nav.getElementsByTagName("h2");
 var t = 2;
 }else{
 var BName = document.getElementById(Nav.id).getElementsByTagName("span");
 var HName = document.getElementById(Nav.id).getElementsByTagName("h1");
 var t = 1;
 }
 for(var i=0; i<HName.length;i++){
 HName[i].innerHTML = HName[i].innerHTML.replace("-","+");
 HName[i].className = "";
 }
 obj.className = "h" + t;
 for(var i=0; i<BName.length; i++){if(i!=n){BName[i].className = "no";}}
 if(BName[n].className == "no"){
 BName[n].className = "";
 obj.innerHTML = obj.innerHTML.replace("+","-");
 }else{
 BName[n].className = "no";
 obj.className = "";
 obj.innerHTML = obj.innerHTML.replace("-","+");
 }
}
//-->
</script>
</head>
<body>
<div id="menu">
 <h1 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 一级菜单A</a></a></h1>
 <span class="no">
 <h2 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 一级菜单A_1</a></a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 一级菜单A_2</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,2)"><a href="javascript:void(0)">+ 一级菜单A_3</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,3)"><a href="javascript:void(0)">+ 一级菜单A_4</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,4)"><a href="javascript:void(0)">+ 一级菜单A_5</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,5)"><a href="javascript:void(0)">+ 一级菜单A_6</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,6)"><a href="javascript:void(0)">+ 一级菜单A_7</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,7)"><a href="javascript:void(0)">+ 一级菜单A_8</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,8)"><a href="javascript:void(0)">+ 一级菜单A_9</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,9)"><a href="javascript:void(0)">+ 一级菜单A_10</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,10)"><a href="javascript:void(0)">+ 一级菜单A_11</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,11)"><a href="javascript:void(0)">+ 一级菜单A_12</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">一级菜单A_0</a>
  <a href="javascript:void(0)">一级菜单A_1</a>
  <a href="javascript:void(0)">一级菜单A_2</a>
  <a href="javascript:void(0)">一级菜单A_3</a>
  <a href="javascript:void(0)">一级菜单A_4</a>
  <a href="javascript:void(0)">一级菜单A_5</a>
  <a href="javascript:void(0)">一级菜单A_6</a>
  <a href="javascript:void(0)">一级菜单A_7</a>
  <a href="javascript:void(0)">一级菜单A_8</a>
  <a href="javascript:void(0)">一级菜单A_9</a>
 </ul>
 </span>
     
 <h1 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 二级菜单B</a></h1>
 <span class="no">
 <h2 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 二级菜单B_1</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">二级菜单B_0</a>
  <a href="javascript:void(0)">二级菜单B_1</a>
  <a href="javascript:void(0)">二级菜单B_2</a>
  <a href="javascript:void(0)">二级菜单B_3</a>
  <a href="javascript:void(0)">二级菜单B_4</a>
  <a href="javascript:void(0)">二级菜单B_5</a>
  <a href="javascript:void(0)">二级菜单B_6</a>
  <a href="javascript:void(0)">二级菜单B_7</a>
  <a href="javascript:void(0)">二级菜单B_8</a>
  <a href="javascript:void(0)">二级菜单B_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 二级菜单B_2</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">二级菜单B_0</a>
  <a href="javascript:void(0)">二级菜单B_1</a>
  <a href="javascript:void(0)">二级菜单B_2</a>
  <a href="javascript:void(0)">二级菜单B_3</a>
  <a href="javascript:void(0)">二级菜单B_4</a>
  <a href="javascript:void(0)">二级菜单B_5</a>
  <a href="javascript:void(0)">二级菜单B_6</a>
  <a href="javascript:void(0)">二级菜单B_7</a>
  <a href="javascript:void(0)">二级菜单B_8</a>
  <a href="javascript:void(0)">二级菜单B_9</a>
 </ul>
 </span>
   
 <h1 onClick="javascript:ShowMenu(this,2)"><a href="javascript:void(0)">+ 三级菜单C</a></h1>
 <span class="no">
 <h2 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 三级菜单C_1</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">三级菜单C_0</a>
  <a href="javascript:void(0)">三级菜单C_1</a>
  <a href="javascript:void(0)">三级菜单C_2</a>
  <a href="javascript:void(0)">三级菜单C_3</a>
  <a href="javascript:void(0)">三级菜单C_4</a>
  <a href="javascript:void(0)">三级菜单C_5</a>
  <a href="javascript:void(0)">三级菜单C_6</a>
  <a href="javascript:void(0)">三级菜单C_7</a>
  <a href="javascript:void(0)">三级菜单C_8</a>
  <a href="javascript:void(0)">三级菜单C_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 三级菜单C_2</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">三级菜单C_0</a>
  <a href="javascript:void(0)">三级菜单C_1</a>
  <a href="javascript:void(0)">三级菜单C_2</a>
  <a href="javascript:void(0)">三级菜单C_3</a>
  <a href="javascript:void(0)">三级菜单C_4</a>
  <a href="javascript:void(0)">三级菜单C_5</a>
  <a href="javascript:void(0)">三级菜单C_6</a>
  <a href="javascript:void(0)">三级菜单C_7</a>
  <a href="javascript:void(0)">三级菜单C_8</a>
  <a href="javascript:void(0)">三级菜单C_9</a>
 </ul>
 </span>
   
 <h1 onClick="javascript:ShowMenu(this,3)"><a href="javascript:void(0)">+ 四级菜单D</a></h1>
 <span class="no">
 <h2 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 四级菜单D_1</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">四级菜单D_0</a>
  <a href="javascript:void(0)">四级菜单D_1</a>
  <a href="javascript:void(0)">四级菜单D_2</a>
  <a href="javascript:void(0)">四级菜单D_3</a>
  <a href="javascript:void(0)">四级菜单D_4</a>
  <a href="javascript:void(0)">四级菜单D_5</a>
  <a href="javascript:void(0)">四级菜单D_6</a>
  <a href="javascript:void(0)">四级菜单D_7</a>
  <a href="javascript:void(0)">四级菜单D_8</a>
  <a href="javascript:void(0)">四级菜单D_9</a>
 </ul>
 <h2 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 四级菜单D_2</a></h2>
 <ul class="no">
  <a href="javascript:void(0)">四级菜单D_0</a>
  <a href="javascript:void(0)">四级菜单D_1</a>
  <a href="javascript:void(0)">四级菜单D_2</a>
  <a href="javascript:void(0)">四级菜单D_3</a>
  <a href="javascript:void(0)">四级菜单D_4</a>
  <a href="javascript:void(0)">四级菜单D_5</a>
  <a href="javascript:void(0)">四级菜单D_6</a>
  <a href="javascript:void(0)">四级菜单D_7</a>
  <a href="javascript:void(0)">四级菜单D_8</a>
  <a href="javascript:void(0)">四级菜单D_9</a>
 </ul>
 </span>
</div>
</body>
</html>