以下代码实现图片的自动滚动的一个功能程序代码，但是以下几句不知道为什么要用到数学函数math,里面的运算我看着一头雾水，能指点下吗？
<script type="text/javascript">
// 7 variables to control behavior
var Car_Image_Width=80;
var Car_Image_Height=50;
var Car_Border=true; // true or false
var Car_Border_Color="red";
var Car_Speed=4;
var Car_Direction=true; // true or false
var Car_NoOfSides=6; // must be 4, 6, 8 or 12
/* array to specify images and optional links.
For 4 sided carousel specify at least 2 images
For 6 sided carousel specify at least 3
For 8 sided carousel specify at least 4
For 12 sided carousel specify at least 6
If Link is not needed keep it ""
*/
Car_Image_Sources=new Array(
"gool.jpg","http://www.cctv.com",
"baidu.jpg","http://www.cctv.com",
"gool.jpg","http://www.cctv.com",
"baidu.jpg","http://www.cctv.com",
"gool.jpg","http://www.cctv.com",
"baidu.jpg","http://www.cctv.com",
"cpcw.jpg","http://www.cctv.com" // NOTE No comma after last line
);
/***************** DO NOT EDIT BELOW **********************************/
CW_I=new Array(Car_NoOfSides/2+1);C_ClcW=new Array(Car_NoOfSides/2);
C_Coef=new Array(
3*Math.PI/2,0,3*Math.PI/2,11*Math.PI/6,Math.PI/6,3*Math.PI/2,7*Math.PI/4, 0,
Math.PI/4,3*Math.PI/2,5*Math.PI/3,11*Math.PI/6,0,Math.PI/6,Math.PI/3);
var C_CoefOf=Car_NoOfSides==4?0:Car_NoOfSides==6?2:Car_NoOfSides==8?5:9;
C_Pre_Img=new Array(Car_Image_Sources.length);
var C_Angle=Car_Direction?Math.PI/(Car_NoOfSides/2):0,C_CrImg=Car_NoOfSides,C_MaxW,C_TotalW,
C_Stppd=false,i,C_LeftOffset,C_HalfNo=Car_NoOfSides/2;
function Carousel(){
if(document.getElementById){
for(i=0;i<Car_Image_Sources.length;i+=2){
C_Pre_Img[i]=new Image();C_Pre_Img[i].src=Car_Image_Sources[i]}
C_MaxW=Car_Image_Width/Math.sin(Math.PI/Car_NoOfSides)+C_HalfNo+1;
Car_Div=document.getElementById("Carousel");
for(i=0;i<C_HalfNo;i++){
CW_I[i]=document.createElement("img");Car_Div.appendChild(CW_I[i]);
CW_I[i].style.position="absolute";
CW_I[i].style.top=0+"px";
CW_I[i].style.height=Car_Image_Height+"px";
if(Car_Border){
CW_I[i].style.borderStyle="solid";
CW_I[i].style.borderWidth=1+"px";
CW_I[i].style.borderColor=Car_Border_Color}
CW_I[i].src=Car_Image_Sources[2*i];
CW_I[i].lnk=Car_Image_Sources[2*i+1];
CW_I[i].onclick=C_LdLnk;
CW_I[i].onmouseover=C_Stp;
CW_I[i].onmouseout=C_Rstrt}
CarImages()}}
function CarImages(){
if(!C_Stppd){
C_TotalW=0;
for(i=0;i<C_HalfNo;i++){
C_ClcW[i]=Math.round(Math.cos(Math.abs(C_Coef[C_CoefOf+i]+C_Angle))*Car_Image_Width);
C_TotalW+=C_ClcW[i]}
C_LeftOffset=(C_MaxW-C_TotalW)/2;
for(i=0;i<C_HalfNo;i++){
CW_I[i].style.left=C_LeftOffset+"px";
CW_I[i].style.width=C_ClcW[i]+"px";
C_LeftOffset+=C_ClcW[i]}
C_Angle+=Car_Speed/720*Math.PI*(Car_Direction?-1:1);
if((Car_Direction&&C_Angle<=0)||(!Car_Direction&&C_Angle>=Math.PI/C_HalfNo)){
if(C_CrImg==Car_Image_Sources.length)C_CrImg=0;
if(Car_Direction){
CW_I[C_HalfNo]=CW_I[0];
for(i=0;i<C_HalfNo;i++)CW_I[i]=CW_I[i+1];
CW_I[C_HalfNo-1].src=Car_Image_Sources[C_CrImg];
CW_I[C_HalfNo-1].lnk=Car_Image_Sources[C_CrImg+1]}
else{ for(i=C_HalfNo;i>0;i--)CW_I[i]=CW_I[i-1];
CW_I[0]=CW_I[C_HalfNo];
CW_I[0].src=Car_Image_Sources[C_CrImg];
CW_I[0].lnk=Car_Image_Sources[C_CrImg+1]}
C_Angle=Car_Direction?Math.PI/C_HalfNo:0;C_CrImg+=2}}
setTimeout("CarImages()",50)}
function C_LdLnk(){if(this.lnk)window.location.href=this.lnk}
function C_Stp(){this.style.cursor=this.lnk?"pointer":"default";C_Stppd=true;}
function C_Rstrt(){C_Stppd=false}
</script>
<div id="Carousel" style="position:absolute; top:306px; left:64px; width: 92px;"><img src="" width="90" height="80"></div>
<body onload="Carousel()">
</body>
这是其中一段：CW_I=new Array(Car_NoOfSides/2+1);C_ClcW=new Array(Car_NoOfSides/2);
C_Coef=new Array(
3*Math.PI/2,0,3*Math.PI/2,11*Math.PI/6,Math.PI/6,3*Math.PI/2,7*Math.PI/4, 0,
Math.PI/4,3*Math.PI/2,5*Math.PI/3,11*Math.PI/6,0,Math.PI/6,Math.PI/3);
var C_CoefOf=Car_NoOfSides==4?0:Car_NoOfSides==6?2:Car_NoOfSides==8?5:9;
C_Pre_Img=new Array(Car_Image_Sources.length);
var C_Angle=Car_Direction?Math.PI/(Car_NoOfSides/2):0,C_CrImg=Car_NoOfSides,C_MaxW,C_TotalW,
C_Stppd=false,i,C_LeftOffset,C_HalfNo=Car_NoOfSides/2;
谢谢哦｀
