在脚本里添加ListBox项后如何在后台获取此项的值？？

Question

 function doSelectOk() {        var objSelected = document.getElementById("lbUserSelected");        var selectItemCount = objSelected.options.length;        var objhfSelectIDList = document.getElementById("hfSelectIDList");        var returnValue = "";        var returnText = "";        for (var i = 0; i < selectItemCount; i++) {            var optionValue = objSelected.options[i].value;            var optionText = objSelected.options[i].text;            if (!IsNull(returnValue)) {                returnValue += ",";                returnText += ",";            }            returnValue += optionValue;            returnText += optionText;        }    var objResult = param;        objhfSelectIDList.valve = param.ValueParam;        alert(objhfSelectIDList.valve);        window.returnValue = objResult;        window.close();    }页面：通过<asp:HiddenField runat="server" />传值在后台里 string IDList = hfSelectIDList.Value.Trim(); 不知道为啥IDList 老是为空！请大家帮忙解决一下哈 谢谢！！！

Answer 1

用javascript等客户端脚本所添加的html项，尽管是有值的，但在后台代码中是获取不出来的，解决办法可以用hiddenfiled解决，javascript控制list的onchange事件，然后写入到hiddenfiled的value中去，然后在后台代码中取hiddenfiled的value值

Answer 2

  alert(objhfSelectIDList.valve); 這裡有 數值嗎？是不是有模板頁哦。