JS里设控件不可用取值

      在JS里面如果设了前台页面的某些控件不可用之后,便不可以在该后台引用该控件的值?如果想引用他怕值则可以在设他不可用之前在JS里将他的值符给一个TEXTBOX然后在后取他的值就可以了例如:

  <td class="tc" style="width: 82px" >領退類別:</td>
       <td style="width: 216px" >
                                &nbsp;<asp:dropdownlist id="ddlfrom"  Runat="server" onchange="onCh2 (this);" Width="207px"  ></asp:dropdownlist><asp:TextBox ID="left1" runat="server" Width="0px"></asp:TextBox>&nbsp;</td>
       <td class="tc" style="width: 72px"  >轉移類型:</td>
       <td style="width: 130px"  >
                                <asp:dropdownlist id="ddlEmpNo"  Runat="server" onchange="onCh(this);" >
         <asp:ListItem Selected="True" Value="0">請選擇</asp:ListItem>
                                <asp:ListItem Value="1">領料</asp:ListItem>
                                <asp:ListItem Value="2">退料</asp:ListItem>
      　</asp:dropdownlist>
      　<asp:TextBox ID="right2" runat="server" Width="0px"></asp:TextBox>
      　</td>



function Addrows2()
{
    var EF012T001=$('txtAddNO').value;
    var EF012T002=$('txtdanhao').value;
    var EF012T003=$('ddlfrom').value;  
    var EF012T004=$('txtlotno').value;
    var EF012T005=$('ddlEmpNo').value;
    var EF012T007=$('txtdatecode').value;
    var EF012T010=$('tbxweixdh').value;
    //取料號說明
   var EF012T011=$('txtguige').value;
 var state=Modules_EForm_drawout_Form.setto(EF012T001,EF012T002,EF012T003,EF012T004,EF012T005,EF012T007,EF012T010,EF012T011).value;
 if(state>0)
 {
     $("left1").value = $("ddlfrom").value;
     $("right2").value = $("ddlEmpNo").value;
     $("ddlfrom").disabled=true;
     $("ddlEmpNo").disabled=true;
 }
 window.thisiframe.location.reload();    
}




function delrows2()
{
 var userid = $('txtAddNO').value ;
 var t=Modules_EForm_drawout_Form.del(SelectItemNo,userid).value;
 var p = $("editBtn");
 p.innerHTML = "<A class=likeBtn1 onclick=\"javascript:;\" href='javascript:;' ><IMG alt=\"\" align=\"absBottom\" border=\"0\"  src=\"../img/xg.gif\"></a>";
 window.thisiframe.location.reload();
 $("tip").style.display='none';
 if(t==0)
 {
     $("left1").value = $("ddlfrom").value;
     $("right2").value = $("ddlEmpNo").value;
     $("ddlfrom").disabled=false;
     $("ddlEmpNo").disabled=false;
 }
}



后台调用:
        ddl1 = this.left1.Text.Trim();
        ddl2 = this.right2.Text.Trim();
         parmDetail[3] = new SqlParameter("@EF012B004", ddl1);
         parmDetail[5] = new SqlParameter("@EF012B006", ddl2);