Jquery 获取下拉列表 选中项的值

今儿做了一个动态联动的下拉列表，但一直无法获取值。搜了搜，有如下定义：

var strValue=$("#select_id").val(); //获取Select选择的Value

varstrText=$("#select_id").find("option:selected").text(); //获取Select选择的text

在jsp页面，使用js写下拉菜单，如下：

<tr>

<td align=right width=40%>车辆所在地</td>

<td colspan=2 width=70%>

<select name="didian" onChange="redirec(document.sellcar.didian.options.selectedIndex)">

<option value=none selected>请选择地区</option>

<option value="beijing">北京</option>

<option value="hebei">河北</option>

<option value="tianjin">天津</option>

<option value="shanxi">山西</option>

<option value="neimeng">内蒙</option>

</select>

<select name="s2">

<option value="请选择" selected>请选择</option>

</select>

<font size=2>(标<font size=2 color=red>*</font>为必填项)</font>

<script language="javascript">

//获取一级菜单长度

var select1_len = document.sellcar.didian.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("海淀区", " ");

select2[1][1] = new Option("通州", " ");

select2[1][2] = new Option("朝阳区", " ");

select2[1][3] = new Option("昌平", " ");

select2[1][4] = new Option("后海", " ");

select2[2][0] = new Option("石家庄", " ");

select2[2][1] = new Option("唐山", " ");

select2[2][2] = new Option("鹿泉", " ");

select2[2][3] = new Option("保定", " ");

select2[2][4] = new Option("沧州", " ");

select2[3][0] = new Option("津南区", " ");

select2[3][1] = new Option("南开区", " ");

select2[3][2] = new Option("和平区", " ");

select2[3][3] = new Option("西青区", " ");

select2[3][4] = new Option("东丽区", " ");

select2[4][0] = new Option("太原", " ");

select2[4][1] = new Option("阳泉", " ");

select2[4][2] = new Option("大同", " ");

select2[4][3] = new Option("临汾", " ");

select2[4][4] = new Option("运城", " ");

select2[5][0] = new Option("赤峰", " ");

select2[5][1] = new Option("呼和浩特", " ");

select2[5][2] = new Option("呼伦贝尔市", " ");

select2[5][3] = new Option("包头", " ");

select2[5][4] = new Option("鄂尔多斯", " ");

//联动函数

function redirec(x)

{

var temp = document.sellcar.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>

</tr>

而Jquery中这样写js：

var didian=$('select[name="didian"]').find("option:selected").text();

didian+=$('select[name="s2"]').find("option:selected").text();

注意第二行的加号！

问题解决！