js实现简洁大方的二级下拉菜单效果代码

2019-11-20 11:37:44

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本文实例讲述了js实现简洁大方的二级下拉菜单效果代码。分享给大家供大家参考。具体如下：

这是一款简洁大方的二级下拉菜单，菜单的颜色自己根据需要重新定义吧，这里仅给大家提供一种制作二级菜单的思路，整体效果看上去相当实用，下拉导航菜单也是大家比较常用的。

运行效果截图如下：

在线演示地址如下：

http://demo.VeVB.COm/js/2015/js-simple-2level-show-down-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><title>简洁大方的二级下拉菜单</title><meta http-equiv="content-type" content="text/html;charset=gb2312"><style type="text/css">*{margin:0;padding:0;font-style:normal;font-family:宋体;}body{text-align:center;font-size:14px;}#content{margin:0 auto;width:600px;}#content #nav{background:#006400;height:32px;margin-top:10px;}#content #nav ul{list-style:none;}#content #nav ul li{float:left;width:100px;line-height:32px;position:relative;}#nav div{width:100px;position:absolute;left:0px;padding-bottom:0px;background:#006400;float:left;height:0;overflow:hidden;}#content #nav li .a{text-decoration:none;color:#00CD00;line-height:32px;display:block;border-right:1px solid #009800;}#nav div a{text-decoration:none;color:#00CD00;line-height:26px;display:block;}#nav div a:hover{background:#005400;}</style></head><body><div id="content"> <div id="nav">  <ul id="supnav">   <li><a href="#" class="a">菜单项1</a>    <div>     <a href="#">菜单测试1</a>     <a href="#">菜单测试1</a>     <a href="#">菜单测试1</a>    </div>   </li>   <li><a href="#" class="a">菜单项2</a>    <div>     <a href="#">菜单测试2</a>     <a href="#">菜单测试2</a>     <a href="#">菜单测试2</a>    </div>   </li>   <li><a href="#" class="a">菜单项3</a>    <div>     <a href="#">菜单测试3</a>     <a href="#">菜单测试3</a>     <a href="#">菜单测试3</a>     <a href="#">菜单测试3</a>     <a href="#">菜单测试3</a>    </div>   </li>   <li><a href="#" class="a">菜单项4</a>    <div>     <a href="#">菜单测试4</a>     <a href="#">菜单测试4</a>     <a href="#">菜单测试4</a>    </div>   </li>   <li><a href="#" class="a">菜单项5</a>    <div>     <a href="#">菜单测试5</a>     <a href="#">菜单测试5</a>     <a href="#">菜单测试5</a>     <a href="#">菜单测试5</a>    </div>   </li>   <li><a href="#" class="a">菜单项6</a>    <div>     <a href="#">菜单测试6</a>     <a href="#">菜单测试6</a>     <a href="#">菜单测试6</a>    </div>   </li>  </ul> </div></div><script type="text/javascript">var supnav=document.getElementById("supnav");var nav=document.getElementById("nav");var btns=document.getElementsByTagName("li");var subnavs=nav.getElementsByTagName("div");var paddingbottom=20;var defaultHeight=0;function drop(obj,ivalue){ var a=obj.offsetHeight; var speed=(ivalue-obj.offsetHeight)/8; a+=Math.floor(speed); obj.style.height=a+"px";}window.onload=function(){ for(var i=0;i<btns.length;i++){  btns[i].index=i;  btns[i].onmouseover=function(){   var osubnav=subnavs[this.index];   var sublinks=osubnav.getElementsByTagName("a");   if(osubnav.firstChild.tagName==undefined){    var itarheight=parseInt(osubnav.childNodes[1].offsetHeight)*sublinks.length+paddingbottom;   }else{    var itarheight=parseInt(osubnav.firstChild.offsetHeight)*sublinks.length+paddingbottom;   }   clearInterval(this.itimer);   this.itimer=setInterval(function(){drop(osubnav,itarheight);},30);  }  btns[i].onmouseout=function(){   var osubnav=subnavs[this.index];   clearInterval(this.itimer);   this.itimer=setInterval(function(){drop(osubnav,defaultHeight);},30);  } }}</script></body></html>

希望本文所述对大家的javascript程序设计有所帮助。

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