本文实例讲述了JS实现光滑展开合拢的菜单效果代码。分享给大家供大家参考。具体如下：
这是一个光滑展开又合拢的JS菜单效果，无jQuery插件，完全JavaScript代码实现，没有过多修饰，有兴趣的美化一下，肯定是款不错的折叠菜单。
运行效果截图如下：
在线演示地址如下：
http://demo.phpstudy.net/js/2015/js-swift-fade-in-out-menu-style-codes/
具体代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3c.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="html/txt; charset=utf-8" />
<title>光滑展开合拢的JS菜单效果</title>
<style>
*{margin:0;padding:0;}
ul,li{list-style:none;}
#con{width:164px; margin:50px auto 0;}
#con h4.top{ height:4px; width:164px; overflow:hidden;}
#con h4.bottom{height:4px; width:164px;overflow:hidden;}
#con div{height:0px; overflow:hidden;}
#con h3{border-top:2px solid #fff; border-bottom:1px solid #D6EFFF;}
</style>
<script language="javascript">
var speed = 30;
var oCon = null;
var oH3List = null;
var oDivList = null;
var oUlList = null;
var oldNum = null;
var clickNum = null;
var hideTimer=null;
var showTimer=null;
window.onload=function(){
oCon = document.getElementById("con");
oH3List = oCon.getElementsByTagName("h3");
oUlList = oCon.getElementsByTagName("ul");
oDivList = oCon.getElementsByTagName("div");
for(var i=0;i<oUlList.length;i++){
oH3List[i].xuhao=i;
oH3List[i].onclick=function(){
clickNum =this.xuhao;
changeCatalog();
};
}
}
function changeCatalog(){
var old_num_2,click_num_2;
old_num_2 = null;
click_num_2= null;
if(oldNum==null){
click_Num_2=clickNum;
showTimer = setInterval("showUl("+click_Num_2+")",speed);
}else if(oldNum == clickNum){
old_num_2=oldNum;
hideTimer = setInterval("hideUl("+old_num_2+")",speed);
}else{
old_num_2=oldNum;
click_num_2=clickNum;
hideTimer = setInterval("hideUl("+old_num_2+")",speed);
showTimer = setInterval("showUl("+click_num_2+")",speed);
}
}
function showUl(num){
var move_num1 =Math.ceil((oUlList[num].offsetHeight-oDivList[num].offsetHeight)/10);
if(move_num1>=1){
oDivList[num].style.height = oDivList[num].offsetHeight+move_num1+"px";
}else{
oldNum=num;
clearInterval(showTimer);
}
}
function hideUl(num){
var move_num2=Math.ceil((oDivList[num].offsetHeight)/10);
if(move_num2>0){
oDivList[num].style.height=oDivList[num].offsetHeight -move_num2+"px";
}else{
clearInterval(hideTimer);
if(clickNum==num){
oldNum=null;
}
}
}
</script>
</head>
<body>
<div id="con">
<h4 class="top"></h4>
<h1></h1>
<h3>设计素材</h3>
<div>
<ul>
<li>精品图标</li>
<li>图片幻灯</li>
<li>网页播放器</li>
</ul>
</div>
<h3>模板素材</h3>
<div>
<ul>
<li>企业网站</li>
<li>儿童网站</li>
<li>音乐网站</li>
<li>Discuz模板</li>
</ul>
</div>
<h3>脚本下载</h3>
<div>
<ul>
<li>jQuery</li>
<li>Ajax</li>
<li>PHP</li>
</ul>
</div>
<h3>网页特效</h3>
<div>
<ul>
<li>菜单</li>
<li>表单</li>
<li>浏览器</li>
</ul>
</div>
<h4 class="bottom"></h4>
</div>
</body>
</html>
希望本文所述对大家的JavaScript程序设计有所帮助。