javascript模拟评分控件实现方法

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>动态设置style(评分效果)</title>
<script type="text/javascript">
//查找一个元素在数组中的索引位置
function ArrayIndexOf(arr, element) {
  for (var i = 0; i < arr.length; i++) {
  if (arr[i] == element) {
   return i;
  }
 }
  return -1;
}
function IniEvent() {
  var tbl = document.getElementById("tblRating");
  var tds = tbl.getElementsByTagName("td");
  for (var i = 0; i < tds.length; i++) {
 var td = tds[i];
 td.onclick = tdOnClick;
 td.style.cursor = "pointer"; //设置光标手型
  }
}
function tdOnClick() {
  var tbl = document.getElementById("tblRating");
  var tds = tbl.getElementsByTagName("td");
  //查找当前点击的td的索引
   var index = ArrayIndexOf(tds, this);
  //之前的td改为红色
  for (var i = 0; i <= index; i++) {
  tds[i].style.background = "red";
  }
  //之后的td改为白色
  for (var i = index + 1; i < tds.length; i++) {
   tds[i].style.background = "white";
  }
}
</script>
</head>
<body onload="IniEvent()">
  <table id="tblRating">
  <tr>
    <td>☆</td>
    <td>☆</td>
    <td>☆</td>
    <td>☆</td>
    <td>☆</td>
  </tr>
  </table>
</body>
</html>