网上下载的代码 放进我的网页里从居中对齐变成做对齐了 调 了好久 不知道怎么办

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/* 懒人图库 搜集整理 www.lanrentuku.com */*{ margin:0; padding:0; list-style:none;}#divSmallBox{overflow:hidden;*display:inline;*zoom:1;width:10px;height:10px;margin:0 5px;border-radius:10px;background:#ffffff;}#playBox{ width:1000px; height:409px; margin:20px auto; background:#333; position:relative; overflow:hidden;}#playBox .oUlplay { width:99999px; position:absolute; left:0; top:0;}#playBox .oUlplay li{ float:left;}#playBox .pre{ cursor:pointer; width:45px; height:45px; background:url(../images/l.png) no-repeat; position:absolute; top:190px; left:10px; z-index:10;}#playBox .next{ cursor:pointer; width:45px; height:45px; background:url(../images/r.png) no-repeat; position:absolute; top:190px; right:10px; z-index:10;}#playBox .smalltitle {width:1000px; height:10px; position:absolute; bottom:15px; z-index:10}#playBox .smalltitle ul{ width:120px; margin:0 auto;}#playBox .smalltitle ul li{ width:10px; height:10px; margin:0 5px; border-radius:10px; background:#ffffff; float:left; overflow:hidden;*display:inline;*zoom:1;}#playBox .smalltitle .thistitle{ background:#69aaec;}上面是css样式function getStyle(obj,name){ if(obj.currentStyle) { return obj.currentStyle[name] } else { return getComputedStyle(obj,false)[name] }}function getByClass(oParent,nClass){ var eLe = oParent.getElementsByTagName('*'); var aRrent  = []; for(var i=0; i<eLe.length; i++) { if(eLe[i].className == nClass) { aRrent.push(eLe[i]); } } return aRrent;}function startMove(obj,att,add){ clearInterval(obj.timer) obj.timer = setInterval(function(){   var cutt = 0 ;   if(att=='opacity')   {   cutt = Math.round(parseFloat(getStyle(obj,att)));   }   else   {   cutt = Math.round(parseInt(getStyle(obj,att)));   }   var speed = (add-cutt)/4;   speed = speed>0?Math.ceil(speed):Math.floor(speed);   if(cutt==add)   {   clearInterval(obj.timer)   }   else   {   if(att=='opacity')   {   obj.style.opacity = (cutt+speed)/100;   obj.style.filter = 'alpha(opacity:'+(cutt+speed)+')';   }   else   {   obj.style[att] = cutt+speed+'px';   }   }    },30)}  window.onload = function()  {  var oDiv = document.getElementById('playBox');  var oPre = getByClass(oDiv,'pre')[0];  var oNext = getByClass(oDiv,'next')[0];  var oUlBig = getByClass(oDiv,'oUlplay')[0];  var aBigLi = oUlBig.getElementsByTagName('li');  var oDivSmall = getByClass(oDiv,'smalltitle')[0]  var aLiSmall = oDivSmall.getElementsByTagName('li');    function tab()  {     for(var i=0; i<aLiSmall.length; i++)     {    aLiSmall[i].className = '';     }     aLiSmall[now].className = 'thistitle'     startMove(oUlBig,'left',-(now*aBigLi[0].offsetWidth))  }  var now = 0;  for(var i=0; i<aLiSmall.length; i++)  {  aLiSmall[i].index = i;  aLiSmall[i].onclick = function()  {  now = this.index;  tab();  } }  oPre.onclick = function()  {  now--  if(now ==-1)  {  now = aBigLi.length;  }   tab();  }   oNext.onclick = function()  {   now++  if(now ==aBigLi.length)  {  now = 0;  }  tab();  }  var timer = setInterval(oNext.onclick,3000) //滚动间隔时间设置  oDiv.onmouseover = function()  {  clearInterval(timer)  }   oDiv.onmouseout = function()  {  timer = setInterval(oNext.onclick,3000) //滚动间隔时间设置  }  }上面是js代码