本文实例为大家分享了js实现导航栏上下动画的具体代码，供大家参考，具体内容如下
obj.currentStyle[name] 与 getComputedStyle(obj,false)[name]，一个是支持IE 一个支持FE
完美运动js插件，能根据传进来的值，进行匹配，从而得到了理想的运动效果，也就是运行逻辑。
实现上下动画动画效果就是控制元素height的值，通过不断的修改该值，就能呈现所谓的动画效果，这里就需要用到定时器
定时器有两种
重复不断的定时器 setInterval(fn,time);
延时只在设定时间后只出现一次的定时器 setTimeout(fn,time)
在遍历传进的每一个值，需要使用一个boolean来控制是否完成解析，解析成功则返回true，结束定时器，返回false,知道返回true位置
function getStyle(obj, attr)
{
if(obj.currentStyle)
{
return obj.currentStyle[attr];
}
else
{
return getComputedStyle(obj, false)[attr];
}
}
function startMove(obj,json,fnEnd){
if(obj.timer){
clearInterval(obj.timer);
};
obj.timer=setInterval(function(){
var bStop = true; //假设全部找到
for(var attr in json){
var icurr = 0;
if(attr=='opacity'){//匹配key
icurr=Math.round(parseFloat(getStyle(obj,attr))*100); //获取元素的属性值
}else{
icurr=parseInt(getStyle(obj,attr));
};
var sPeed = (json[attr]-icurr)/8;
sPeed=sPeed>0?Math.ceil(sPeed):Math.floor(sPeed);
if(attr=='opacity'){
obj.style.filter="alpha(opacity:"+(icurr+sPeed)+")";
obj.style.opacity=(icurr+sPeed)/100;
}else{
obj.style[attr]=icurr+sPeed+'px';
}
if(icurr!=json[attr]){
bStop=false;
}
}
if(bStop){
clearInterval(obj.timer);
if(fnEnd){
fnEnd();
}
}
},30);
}
// alert('dffe');
html布局
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<link rel="stylesheet" type="text/css" href="css/common.css" />
<script src="js/move.js"></script>
<script src="js/common.js"></script>
<title></title>
</head>
<body>
<div id="box">
<div><a href="javascript:;" class="a01"></a><em>关于</em><span></span></div>
<div><a href="javascript:;" class="a02"></a><em>招聘</em><span></span></div>
<div><a href="javascript:;" class="a04"></a><em>产品</em><span></span></div>
<div><a href="javascript:;" class="a03"></a><em>公司</em><span></span></div>
</div>
</body>
</html>
css文件
*{
margin: 0;
padding: 0;
}
a{
text-decoration: none;
}
body{
background-color: #c1c1c1;
}
#box{
width: 880px;
margin: 100px auto;
overflow: hidden;
}
#box div{
width: 200px;
height: 100px;
float: left;
overflow: hidden;
position: relative;
}
#box div a{
position: absolute;
left: 0;
top: 0;
width: 200px;
height: 100px;
display: block;
/* background-color: red; */
background: url(../images/1.webp) no-repeat;
}
#box div span{
display: block;
width: 200px;
height: 100px;
position: absolute;
background: url(../images/window.webp) left top repeat-x;
}
#box div em{
display: block;
width: 100%;
height: 100%;
background-color: #999;
position: absolute;
text-align: center;
line-height: 100px;
font-family: Verdana;
font-style: normal;
font-size: 30px;
color: white;
text-shadow: 2px 1px 4px black;
top: 0;
}
#box div a.a01{
/* background: url(../images/1.webp) 0 5px no-repeat; */
background-position: 0 5px;
}
#box div a.a02{
/* background: url(../images/1.webp) 0 5px no-repeat; */
background-position: -200px 5px;
}
#box div a.a03{
/* background: url(../images/1.webp) 0 5px no-repeat; */
background-position: -400px 5px;
}
#box div a.a04{
/* background: url(../images/1.webp) 0 5px no-repeat; */
background-position: -600px 5px;
}
window.οnlοad=fn
window.onload=function(){
var oDiv = document.getElementById('box');
var aDiv = oDiv.getElementsByTagName('div');
var aEm = oDiv.getElementsByTagName('em');
var aEm = oDiv.getElementsByTagName('em');
for(var i=0;i<aDiv.length;i++)
{
aDiv[i].index = i;
aDiv[i].onmouseover = function()
{
startMove(aEm[this.index],{top:-aEm[this.index].offsetHeight})
}
aDiv[i].onmouseout = function()
{
startMove(aEm[this.index],{top:0})
}
}
}
