javascript做二级联动

<% ... @pagecontentType = " text/html;charset=UTF-8 " %>
< html >
< head >
< title > Thisisatest! </ title >
</ head >
< body >
< form name ="frm" >
< select name ="s1" onChange ="redirec(document.frm.s1.options.selectedIndex)" >
< option selected > 请选择 </ option >
< option value ="1" > 脚本语言 </ option >
< option value ="2" > 高级语言 </ option >
< option value ="3" > 其他语言 </ option >
</ select >

< select name ="s2" >
< option value ="请选择" selected > 请选择 </ option >
</ select >
</ form >
< script language ="javascript" > ...
// 获取一级菜单长度
var select1_len = document.frm.s1.options.length;
var select2 = new Array(select1_len);
// 把一级菜单都设为数组
for (i = 0 ;i < select1_len;i ++ )
... {select2[i] = new Array();
}
// 定义基本选项
select2[ 0 ][ 0 ] = new Option( " 请选择 " , " " );

select2[ 1 ][ 0 ] = new Option( " PHP " , " " );
select2[ 1 ][ 1 ] = new Option( " ASP " , " " );
select2[ 1 ][ 2 ] = new Option( " JSP " , " " );

select2[ 2 ][ 0 ] = new Option( " C/C++ " , " " );
select2[ 2 ][ 1 ] = new Option( " Java " , " " );
select2[ 2 ][ 2 ] = new Option( " C# " , " " );
select2[ 2 ][ 3 ] = new Option( " hibernate " , " " );

select2[ 3 ][ 0 ] = new Option( " Perl " , " " );
select2[ 3 ][ 1 ] = new Option( " Ruby " , " " );
select2[ 3 ][ 2 ] = new Option( " Python " , " " );
// 联动函数
function redirec(x)
... {
var temp = document.frm.s2;
for (i = 0 ;i < select2[x].length;i ++ )
... {
temp.options[i] = new Option(select2[x][i].text,select2[x][i].value);
}
temp.options[ 0 ].selected = true ;
}
</ script >
</ body > fdsafdsf
</ html >