帮忙看看这个JS哪有问题

复制内容到剪贴板

代码:

<script language='javascript'>
var curStyle = 1;
var totalItem = 7;
function changeSel(itemnum){
  curStyle = itemnum;
  for(i=1;i<=totalItem;i++)
  {
     if(document.getElementById('item'+i)) document.getElementById('item'+i).className='';
  }
  document.getElementById('item'+itemnum).className='on';
}
</script>
<div id="pri-nav">
    <div class="span"></div>
        <ul>
            <li id='item1' onclick="changeSel(1)" class="on"><a href="#"><span>首页</span></a></li>
            <li id='item2' onclick="changeSel(2)"><a href="#"><span>核心</span></a></li>
            <li id='item3' onclick="changeSel(3)"><a href="#"><span>模块</span></a></li>
            <li id='item4' onclick="changeSel(4)"><a href="#"><span>采集</span></a></li>
            <li id='item5' onclick="changeSel(5)"><a href="#"><span>模板</span></a></li>
            <li id='item6' onclick="changeSel(6)"><a href="{spUrl c=main a=member}" target="leftFrame"><span>会员</span></a></li>
            <li id='item7' onclick="changeSel(7)"><a href="{spUrl c=main a=system}" target="leftFrame"><span>系统</span></a></li>
        </ul>
    </div><!--end pri-nav-->

复制内容到剪贴板

代码:

for(i=1;i<=totalItem;i++)