jsp servlet select 傳值

//jsp

<script language="javascript">
  function loginIn(){
  var selectOb= document.getElementById("select");//select對象  
  var selectText=  selectOb.options[selectOb.selectedIndex].text//得到文本   
  //1.var selectOb= document.getElementById("selectObId");//select對象   
  //2.var selectId = selectOb.selectedIndex;//當前選擇的索引   
  //3.var selectValue=  selectOb.options[selectOb.selectedIndex].value//得到值   
  //4.var selectText=  selectOb.options[selectOb.selectedIndex].text//得到文本   
  //5.selectOb.options.length = 0//清空   
  //6.selectOb.options[0] = new Option("text",'value');//添加資料  
   form9.action="servlet/loginServlet?selectt="+selectText; 
   form9.submit();
  }
 </script>

<form name="form9"  method="post">

<select name="select" size="1" id="select" onchange="loginIn();"> 
        <%
      String sql = "select username from user where adminname='"   + session.getAttribute("adminname") + "'";
      ResultSet rs = db.query(sql);
      while (rs.next()) {
     %>
        <option value=><%=rs.getString("username")%></option>
     <%
      }
     %>
       </select>

</form>

//servlet

String selectname=request.getParameter("selectt");