C# select的联动效果

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>JS联动下拉框</title>
<script language="javascript" >
/* 
**    ====================================
**    类名：CLASS_LIANDONG_YAO 
**    功能：多级连动菜单 
**/   
  function CLASS_LIANDONG_YAO(array)
  {
   //数组，联动的数据源
   this.array=array;
   this.indexName='';
   this.obj='';
   //设置子SELECT
 // 参数：当前onchange的SELECT ID，要设置的SELECT ID
      this.subSelectChange=function(selectName1,selectName2)
   {
   //try
   //{
    var obj1=document.all[selectName1];
    var obj2=document.all[selectName2];
    var objName=this.toString();
    var me=this;
    obj1.onchange=function()
    {
     me.optionChange(this.options[this.selectedIndex].value,obj2.id)
    }
   }
   //设置第一个SELECT
 // 参数：indexName指选中项,selectName指select的ID
   this.firstSelectChange=function(indexName,selectName) 
   {
   this.obj=document.all[selectName];
   this.indexName=indexName;
   this.optionChange(this.indexName,this.obj.id)
   }
  // indexName指选中项,selectName指select的ID
   this.optionChange=function (indexName,selectName)
   {
    var obj1=document.all[selectName];
    var me=this;
    obj1.length=0;
    obj1.options[0]=new Option("请选择",'');
    for(var i=0;i<this.array.length;i++)
    { 
     if(this.array[i][1]==indexName)
     {
     //alert(this.array[i][1]+" "+indexName);
      obj1.options[obj1.length]=new Option(this.array[i][2],this.array[i][0]);
     }
    }
   } 
  }
  </script>
</head>
<body>
<form name="form1" method="post">
   &nbsp;
   <SELECT ID="s1" NAME="s1"  >
    <OPTION selected></OPTION>
   </SELECT>
   <SELECT ID="s2" NAME="s2"  >
    <OPTION selected></OPTION>
   </SELECT>
   <SELECT ID="s3" NAME="s3">
    <OPTION selected></OPTION>
   </SELECT>
   <br>
   <br><br>
   <SELECT ID="x1" NAME="x1"  >
    <OPTION selected></OPTION>
   </SELECT>
   <SELECT ID="x2" NAME="x2"  >
    <OPTION selected></OPTION>
   </SELECT>
   <SELECT ID="x3" NAME="x3">
    <OPTION selected></OPTION>
   </SELECT>
   <SELECT ID="x4" NAME="x4">
    <OPTION selected></OPTION>
   </SELECT>
   <SELECT ID="x5" NAME="x5">
    <OPTION selected></OPTION>
   </SELECT>
   
  </form>
 </body>
 
 
<script language="javascript">
//例子1-------------------------------------------------------------
//数据源
var array=new Array();
  array[0]=new Array("华南地区","根目录","华南地区"); //数据格式 ID，父级ID，名称
  array[1]=new Array("华北地区","根目录","华北地区");
  array[2]=new Array("上海","华南地区","上海");
  array[3]=new Array("广东","华南地区","广东");
  array[4]=new Array("徐家汇","上海","徐家汇");
  array[5]=new Array("普托","上海","普托"); 
  array[6]=new Array("广州","广东","广州");
  array[7]=new Array("湛江","广东","湛江");
  //--------------------------------------------
  //这是调用代码
  var liandong=new CLASS_LIANDONG_YAO(array) //设置数据源
  liandong.firstSelectChange("根目录","s1"); //设置第一个选择框
  liandong.subSelectChange("s1","s2"); //设置子级选择框
  liandong.subSelectChange("s2","s3");
 
 
 //例子2-------------------------------------------------------------
 //数据源 
  var array2=new Array();//数据格式 ID，父级ID，名称
  array2[0]=new Array("测试测试","根目录","测试测试");
  array2[1]=new Array("华北地区","根目录","华北地区");
  array2[2]=new Array("上海","测试测试","上海");
  array2[3]=new Array("广东","测试测试","广东");
  array2[4]=new Array("徐家汇","上海","徐家汇");
  array2[5]=new Array("普托","上海","普托"); 
  array2[6]=new Array("广州","广东","广州");
  array2[7]=new Array("湛江","广东","湛江");
  array2[8]=new Array("不知道","湛江","不知道");
  array2[9]=new Array("5555","湛江","555");
  array2[10]=new Array("++++","不知道","++++");
  array2[11]=new Array("111","徐家汇","111");
  array2[12]=new Array("222","111","222");
  array2[13]=new Array("333","222","333");
  //--------------------------------------------
  //这是调用代码
  //设置数据源
  var liandong2=new CLASS_LIANDONG_YAO(array2);
  //设置第一个选择框
  liandong2.firstSelectChange("根目录","x1");
  //设置子选择框
  liandong2.subSelectChange("x1","x2")
  liandong2.subSelectChange("x2","x3")
  liandong2.subSelectChange("x3","x4")
  liandong2.subSelectChange("x4","x5")
</script>
</html>