JS实现适合于后台使用的动画折叠菜单效果

本文实例讲述了JS实现适合于后台使用的动画折叠菜单效果。分享给大家供大家参考。具体如下：

这是一款适合于后台使用的动画折叠菜单，代码超简，无jQuery，展开与折叠效果平滑。本演示中有两组菜单，向大家展示如何在一个网页中布局两个菜单，整体效果以及兼容性还算可以，希望在实际应用中不会出现什么问题。

运行效果截图如下：

在线演示地址如下：

http://demo.jb51.net/js/2015/js-ht-control-animate-zd-menu-codes/

具体代码如下：

<!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>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>适合于后台使用的动画折叠菜单</title>
<script type="text/javascript">
 function FOLDMenu(id,onlyone){
  if(!document.getElementById || !document.getElementsByTagName){return false;}
  this.menu=document.getElementById(id);
  this.submenu=this.menu.getElementsByTagName("ul");
  this.speed=3;
  this.time=10;
  this.onlyone=onlyone==true?onlyone:false;
  this.links = this.menu.getElementsByTagName("a");
 }
 FOLDMenu.prototype.init=function(){
  var mainInstance = this;
  for(var i=0;i<this.submenu.length;i++){
   this.submenu[i].getElementsByTagName("span")[0].onclick=function(){
    mainInstance.toogleMenu(this.parentNode);
   };
  }
  for(var i=0;i<this.links.length;i++){
   this.links[i].onclick=function(){
    this.className = "current";
    mainInstance.removeCurrent(this);
   }
  }
 }
 FOLDMenu.prototype.removeCurrent = function(link){
   for (var i = 0; i < this.links.length; i++){
    if (this.links[i] != link){
     this.links[i].className = " ";
    }
   }
 }
 FOLDMenu.prototype.toogleMenu=function(submenu){
  if(submenu.className=="open"){
   this.closeMenu(submenu);
  }else{
   this.openMenu(submenu);
  }
 }
 FOLDMenu.prototype.openMenu=function(submenu){
  var fullHeight=submenu.getElementsByTagName("span")[0].offsetHeight;
  var links = submenu.getElementsByTagName("a");
  for (var i = 0; i < links.length; i++){
   fullHeight += links[i].offsetHeight;
  }
   var moveBy = Math.round(this.speed * links.length);
   var mainInstance = this;
    var intId = setInterval(function() {
     var curHeight = submenu.offsetHeight;
     var newHeight = curHeight + moveBy;
     if (newHeight <fullHeight){
      submenu.style.height = newHeight + "px";
     }else {
      clearInterval(intId);
      submenu.style.height = "";
      submenu.className = "open";
     }
    }, this.time);
    this.collapseOthers(submenu);
 }
 FOLDMenu.prototype.closeMenu=function(submenu){
   var minHeight=submenu.getElementsByTagName("span")[0].offsetHeight;
   var moveBy = Math.round(this.speed * submenu.getElementsByTagName("a").length);
   var mainInstance = this;
    var intId = setInterval(function() {
     var curHeight = submenu.offsetHeight;
     var newHeight = curHeight - moveBy;
     if (newHeight > minHeight){
      submenu.style.height = newHeight + "px";
     }else {
      clearInterval(intId);
      submenu.style.height = "";
      submenu.className = "";
     }
    }, this.time);
 }
 FOLDMenu.prototype.collapseOthers = function(submenu){
  if(this.onlyone){
   for (var i = 0; i < this.submenu.length; i++){
    if (this.submenu[i] != submenu){
     this.closeMenu(this.submenu[i]);
    }
   }
  }
 }
</script>
<style type="text/css">
*{margin:0;padding:0;}
.foldmenu{border:1px solid #000;width:150px;margin:50px;}
.foldmenu ul{list-style-type:none;height:25px;line-height:25px;overflow:hidden;cursor:pointer;}
.foldmenu ul.open{height:auto;}
.foldmenu ul span{display:block;padding-left:5px}
.foldmenu ul li{border-bottom:1px solid #DDDDDD;}
.foldmenu li a{background-color:#EEEEEE;color:#006666;display:block;padding:5px 10px;text-decoration:none;text-align:center;}
.foldmenu li a:hover{background-color:#006666;color:#ffffff;}
.foldmenu li a.current{background-color:#006666;color:#ffffff;}
</style>
</head>
<body>
<div id="foldmenu" class="foldmenu" style="float:left;">
 <ul class="open">
  <span>编程天地</span>
 <li><a href="#">电子书籍</a></li>
 <li><a href="#">源码乐园</a></li>
 </ul>
 <ul>
  <span>中国门户</span>
 <li><a href="#">百度搜索</a></li>
 <li><a href="#">新浪新闻</a></li>
  <li><a href="#">腾讯QQ</a></li>
 </ul>
 <ul>
  <span>音乐网站</span>
 <li><a href="#">百度音乐</a></li>
 <li><a href="#">QQ163</a></li>
 </ul>
</div>
<div id="foldmenu2" class="foldmenu" style="float:right;">
 <ul class="open">
  <span>世界大学</span>
 <li><a href="#">剑桥</a></li>
 <li><a href="#">牛津</a></li>
  <li><a href="#">哈佛</a></li>
 <li><a href="#">麻省理工</a></li>
 </ul>
 <ul>
  <span>中国大学</span>
 <li><a href="#">北大</a></li>
 <li><a href="#">清华</a></li>
  <li><a href="#">港大</a></li>
 </ul>
 <ul>
  <span>世界好车</span>
 <li><a href="#">宝马</a></li>
 <li><a href="#">奔驰</a></li>
 <li><a href="#">奥迪</a></li>
 </ul>
 <ul>
  <span>开源论坛</span>
 <li><a href="#">PhpWind</a></li>
 <li><a href="#">Discuz!</a></li>
 </ul>
</div>
<script type="text/javascript">
window.onload = function() {
 myMenu = new FOLDMenu("foldmenu",true);
 myMenu.init();
 myMenu2 = new FOLDMenu("foldmenu2");
 myMenu2.init();
};
</script>
</body>
</html>

希望本文所述对大家的JavaScript程序设计有所帮助。