一个很有趣3D球状标签云兼容IE8_javascript技巧

看见一个很有趣的标签云，3D球状，兼容 IE 8，亲测可用！其他版本没有测试。觉得挺有意思就拿来记录下来，学习学习，本文下方会放出我看的文章地址，先看一下效果：

接下来是代码，html + css + js，不是基于jQuery的，所以不需要引入，代码复制下来就可以看到效果：

<div id="div1">
<a href="http://www.cnblogs.com/ntt1219/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >忘了滋味</a>
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</div>

body {background: #000 url(index.png) no-repeat center 230px;}
#div1 {position:relative; width:450px; height:450px; margin: 20px auto 0; }
#div1 a {position:absolute; top:0px; left:0px; font-family: Microsoft YaHei; color:#fff; font-weight:bold; text-decoration:none; padding: 3px 6px; }
#div1 a:hover {border: 1px solid #eee; background: #000; }
#div1 .blue {color:blue;}
#div1 .red {color:red;}
#div1 .yellow {color:yellow;}

var radius = 120;
var dtr = Math.PI/180;
var d=300;
var mcList = [];
var active = false;
var lasta = 1;
var lastb = 1;
var distr = true;
var tspeed=10;
var size=250;
var mouseX=0;
var mouseY=0;
var howElliptical=1;
var aA=null;
var oDiv=null;
window.onload=function ()
{
var i=0;
var oTag=null;

oDiv=document.getElementById('div1');

aA=oDiv.getElementsByTagName('a');

for(i=0;i<aA.length;i++)
{
oTag={};

oTag.offsetWidth=aA[i].offsetWidth;
oTag.offsetHeight=aA[i].offsetHeight;

mcList.push(oTag);
}

sineCosine( 0,0,0 );

positionAll();

oDiv.onmouseover=function ()
{
active=true;
};

oDiv.onmouseout=function ()
{
active=false;
};

oDiv.onmousemove=function (ev)
{
var oEvent=window.event || ev;

mouseX=oEvent.clientX-(oDiv.offsetLeft+oDiv.offsetWidth/2);
mouseY=oEvent.clientY-(oDiv.offsetTop+oDiv.offsetHeight/2);

mouseX/=5;
mouseY/=5;
};

setInterval(update, 30);
};
function update()
{
var a;
var b;

if(active)
{
a = (-Math.min( Math.max( -mouseY, -size ), size ) / radius ) * tspeed;
b = (Math.min( Math.max( -mouseX, -size ), size ) / radius ) * tspeed;
}
else
{
a = lasta * 0.98;
b = lastb * 0.98;
}

lasta=a;
lastb=b;

if(Math.abs(a)<=0.01 && Math.abs(b)<=0.01)
{
return;
}

var c=0;
sineCosine(a,b,c);
for(var j=0;j<mcList.length;j++)
{
var rx1=mcList[j].cx;
var ry1=mcList[j].cy*ca+mcList[j].cz*(-sa);
var rz1=mcList[j].cy*sa+mcList[j].cz*ca;

var rx2=rx1*cb+rz1*sb;
var ry2=ry1;
var rz2=rx1*(-sb)+rz1*cb;

var rx3=rx2*cc+ry2*(-sc);
var ry3=rx2*sc+ry2*cc;
var rz3=rz2;

mcList[j].cx=rx3;
mcList[j].cy=ry3;
mcList[j].cz=rz3;

per=d/(d+rz3);

mcList[j].x=(howElliptical*rx3*per)-(howElliptical*2);
mcList[j].y=ry3*per;
mcList[j].scale=per;
mcList[j].alpha=per;

mcList[j].alpha=(mcList[j].alpha-0.6)*(10/6);
}

doPosition();
depthSort();
}
function depthSort()
{
var i=0;
var aTmp=[];

for(i=0;i<aA.length;i++)
{
aTmp.push(aA[i]);
}

aTmp.sort
(
function (vItem1, vItem2)
{
if(vItem1.cz>vItem2.cz)
{
return -1;
}
else if(vItem1.cz<vItem2.cz)
{
return 1;
}
else
{
return 0;
}
}
);

for(i=0;i<aTmp.length;i++)
{
aTmp[i].style.zIndex=i;
}
}
function positionAll()
{
var phi=0;
var theta=0;
var max=mcList.length;
var i=0;

var aTmp=[];
var oFragment=document.createDocumentFragment();

//随机排序
for(i=0;i<aA.length;i++)
{
aTmp.push(aA[i]);
}

aTmp.sort
(
function ()
{
return Math.random()<0.5&#63;1:-1;
}
);

for(i=0;i<aTmp.length;i++)
{
oFragment.appendChild(aTmp[i]);
}

oDiv.appendChild(oFragment);

for( var i=1; i<max+1; i++){
if( distr )
{
phi = Math.acos(-1+(2*i-1)/max);
theta = Math.sqrt(max*Math.PI)*phi;
}
else
{
phi = Math.random()*(Math.PI);
theta = Math.random()*(2*Math.PI);
}
//坐标变换
mcList[i-1].cx = radius * Math.cos(theta)*Math.sin(phi);
mcList[i-1].cy = radius * Math.sin(theta)*Math.sin(phi);
mcList[i-1].cz = radius * Math.cos(phi);

aA[i-1].style.left=mcList[i-1].cx+oDiv.offsetWidth/2-mcList[i-1].offsetWidth/2+'px';
aA[i-1].style.top=mcList[i-1].cy+oDiv.offsetHeight/2-mcList[i-1].offsetHeight/2+'px';
}
}
function doPosition()
{
var l=oDiv.offsetWidth/2;
var t=oDiv.offsetHeight/2;
for(var i=0;i<mcList.length;i++)
{
aA[i].style.left=mcList[i].cx+l-mcList[i].offsetWidth/2+'px';
aA[i].style.top=mcList[i].cy+t-mcList[i].offsetHeight/2+'px';

aA[i].style.fontSize=Math.ceil(12*mcList[i].scale/2)+8+'px';

aA[i].style.filter="alpha(opacity="+100*mcList[i].alpha+")";
aA[i].style.opacity=mcList[i].alpha;
}
}
function sineCosine( a, b, c)
{
sa = Math.sin(a * dtr);
ca = Math.cos(a * dtr);
sb = Math.sin(b * dtr);
cb = Math.cos(b * dtr);
sc = Math.sin(c * dtr);
cc = Math.cos(c * dtr);
}