3级联动下拉框：DropDownList加上js后运行提示回发或回调参数无效？？

aspx文件中相关内容：                    <script type="text/javascript" src="region_zh_cn.js"></script>
                    <table width="100%" cellpadding="1" cellspacing="1" class="tabForm">
                        <tr class="trForm" onmouseover="mOvr(this);" onmouseout="mOut(this,'#EFF3FB');">
                            <td width="15%">
                                国家
                            </td>
                            <td width="35%">
                                <asp:DropDownList ID="ddlCountry" runat="server" Width="131px">
                                    <asp:ListItem Value="Not_set">-- 所有国家 --</asp:ListItem>
                                </asp:DropDownList>
                            </td>
                            <td width="15%">
                                省份
                            </td>
                            <td width="35%">
                                <asp:DropDownList ID="ddlProvince" Width="131px" runat="server">
                                    <asp:ListItem Value="Not_set">-- 所有省/直辖市 --</asp:ListItem>
                                </asp:DropDownList>
                            </td>
                        </tr>
                        <tr class="trForm" onmouseover="mOvr(this);" onmouseout="mOut(this,'#EFF3FB');">
                            <td width="15%">
                                城市
                            </td>
                            <td width="35%">
                                <asp:DropDownList ID="ddlCity" Width="131px" runat="server">
                                    <asp:ListItem Value="Not_set">-- 所有城市/区 --</asp:ListItem>
                                </asp:DropDownList>
                            </td>
                            <td width="15%">
                                邮编
                            </td>
                            <td width="35%">
                                <asp:TextBox ID="txtPostCode" runat="server"></asp:TextBox>
                            </td>
                        </tr>
                        <tr class="trForm" onmouseover="mOvr(this);" onmouseout="mOut(this,'#EFF3FB');">
                            <td width="15%">
                                详细地址
                            </td>
                            <td colspan="3">
                                <asp:TextBox ID="txtAddress" runat="server" Width="80%"></asp:TextBox>
                            </td>
                        </tr>
                    </table>//////////////////////////
js文件是地理位置信息数组：var Not_set = new Array();
var country = new Array(
"China","中国大陆",
"MetroChina","港澳台",
"USA","美国",
"Canada","加拿大",
"Europe","欧洲",
"Asia","东南亚",
"Australia","澳大利亚",
"NewZealand","新西兰",
"Japan","日本",
"Korea","韩国",
"Others","其它地区"
) ;................var China = new Array(
"Beijing" , "北京",
"Shanghai" , "上海",
"Tianjin" , "天津",................var Beijing = new Array(
"0" , "东城区",
"1" , "西城区",
"2" , "崇文区",
"3" , "宣武区",
"4" , "朝阳区",................./////////////////////
cs文件相关内容如下：ddlCountry.Attributes.Add("onChange", "change_region(window.document.form1.ddlProvince,window.document.form1.ddlCountry.options[selectedIndex].value );");
ddlProvince.Attributes.Add("onChange", "change_region(window.document.form1.ddlCity,window.document.form1.ddlProvince.options[selectedIndex].value );");string initRegion = "<script language=\"javascript\">set_select_options( window.document.form1.ddlCountry, country, \"Not_set\" ) ;set_select_options( window.document.form1.ddlProvince, Not_set, \"Not_set\" ) ;set_select_options( window.document.form1.ddlCity, Not_set, \"Not_set\" ) ;</script>";Page.ClientScript.RegisterStartupScript(typeof(string), "", initRegion);////////////////////////////
运行时点击保存按钮后就出现错误：回发或回调参数无效。在配置中使用 <pages enableEventValidation="true"/> 或在页面中使用 <%@ Page EnableEventValidation="true" %> 启用了事件验证。出于安全目的，此功能验证回发或回调事件的参数是否来源于最初呈现这些事件的服务器控件。如果数据有效并且是预期的，则使用 ClientScriptManager.RegisterForEventValidation 方法来注册回发或回调数据以进行验证。