javascript元素3D旋转效果代码实例
分类：实例代码
本章节分享一段代码实例，它实现了元素的3D旋转效果。
里面涉及到一些数学相关的东西，感兴趣的朋友可以自行进行一下分析。
代码实例如下:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="author" content="http://www.pipipi.net/" />
<title>前端教程网</title>
<style type="text/css">
#show{
position:relative;
margin:20px auto;
width:800px;
}
.item{
position:absolute;
height:40px;
width:60px;
background:#999999;
border:1px solid #eeeeee;
cursor:pointer;
}
</style>
<script type="text/javascript">
var len;
var showerObj;
var listObj;
var showerWidth=800;
var showerHeight=400;
var r;
var cR=0;
var ccR=0;
var timer=0;
window.onload=function(){
showerObj=document.getElementById("show");
listObj=showerObj.getElementsByTagName("div");
len=listObj.length;
r=Math.PI/180*360/len;
for(var i=0;i<len;i++){
var item=listObj[i];
item.style.top=showerHeight/2+Math.sin(r*i)*showerWidth/2-20+"px";
item.style.left=showerWidth/2+Math.cos(r*i)*showerWidth/2-30+"px";
item.rotate=(r*i+2*Math.PI)%(2*Math.PI);
item.onclick=function(){
cR=Math.PI/2-this.rotate;
timer || (timer=setInterval(rotate,10));
}
}
var rX=showerObj.offsetLeft+showerWidth/2;
var ry=showerObj.offsetTop+showerHeight/2;
var rotate=function(){
ccR=(ccR+2*Math.PI)%(2*Math.PI);
if(cR-ccR<0) cR=cR+2*Math.PI;
if(cR-ccR<Math.PI){
ccR=ccR+(cR-ccR)/19;
}
else{
ccR=ccR-(2*Math.PI+ccR-cR)/19;
}
if(Math.abs((cR+2*Math.PI)%(2*Math.PI)-(ccR+2*Math.PI)%(2*Math.PI))<Math.PI/720){
ccR=cR;
clearInterval(timer);
timer=0;
}
for(var i=0;i<len;i++){
var item = listObj[i];
var w,h;
var sinR=Math.sin(r*i+ccR);
var cosR=Math.cos(r*i+ccR);
w=60+0.6*60*sinR;
h=(40+0.6*40*sinR);
item.style.cssText
+=";width:"
+w+"px;height:"
+h+"px;top:"
+parseInt(showerHeight/2+sinR*showerWidth/2/3-w/2)
+"px;left:"
+parseInt(showerWidth/2+cosR*showerWidth/2-h/2)
+"px;z-index:"
+parseInt(showerHeight/2+sinR*showerWidth/2/3-w/2)+";";
}
}
document.getElementById("l").onclick=function(){
cR=(cR+r+2*Math.PI)%(2*Math.PI);
timer || (timer=setInterval(rotate,10));
}
document.getElementById("r").onclick=function(){
cR=(cR-r+2*Math.PI)%(2*Math.PI);
timer || (timer=setInterval(rotate,10));
}
rotate();
}
</script>
</head>
<body>
<input id="l" type="button" value="left" />
<input id="r" type="button" value="right" />
<div id="show">
<div class="item">1</div>
<div class="item">2</div>
<div class="item">3</div>
<div class="item">4</div>
<div class="item">5</div>
<div class="item">6</div>
<div class="item">7</div>
<div class="item">8</div>
<div class="item">9</div>
<div class="item">0</div>
<div class="item">a</div>
<div class="item">b</div>
<div class="item">1</div>
<div class="item">2</div>
<div class="item">3</div>
</div>
</body>
</html>