用table显示n条记录，每三条换一下颜色

<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
   
    <title>用table显示n条记录，每三行换一次颜色</title>
   
 

  </head>
 
  <body>
<table id="tbl">
 <tr><td>1</td></tr>
 <tr><td>2</td></tr>
 <tr><td>3</td></tr>
 <tr><td>4</td></tr>
 <tr><td>5</td></tr>
 <tr><td>6</td></tr>
 <tr><td>7</td></tr>
 <tr><td>8</td></tr>
 <tr><td>9</td></tr>
 <tr><td>10</td></tr>
</table>

<script type="text/javascript">
 window.onload=function()
  {
   var tbl = document.getElementById("tbl");
   rows = tbl.getElementsByTagName("tr");
   for(i=0;i<rows.length;i++)
   {
    var j = parseInt(i/3);
    if(j%2==0) rows[i].style.backgroundColor="#f00";
    else  rows[i].style.backgroundColor="#0f0";
   }
  }
</script>
  </body>
</html>