在Telerik RadGrid中保留所选项目（分页，排序，过滤）

我正在使用Telerik RadGrid，我需要通过分页，排序和过滤来保留所选项目 . 我找到了this示例并尝试了他们的示例并获得了混合结果 . 有时它可以在Chrome中运行，虽然非常有缺陷（有时一次只允许一次选择） . 当我在IE中运行它时出现此错误

无法获取属性'get_element'对象的值为null或未定义

这是我正在使用的代码：

<telerik:RadScriptBlock ID="RadScriptBlock1" runat="server">
    <script type="text/javascript">
            var selected = {};
            function RadGrid_RowSelected(sender, args) {
                var rfp = args.getDataKeyValue("RFPID");
                if (!selected[rfp]) {
                    selected[rfp] = true;
                }
            }
            function RadGrid_RowDeselected(sender, args) {
                var rfp = args.getDataKeyValue("RFPID");
                if (selected[rfp]) {
                    selected[rfp] = null;
                }
            }
            function RadGrid_RowCreated(sender, args) {
                var rfp = args.getDataKeyValue("RFPID");
                if (selected[rfp]) {
                    args.get_gridDataItem().set_selected(true);
                }
            }
            function RadGrid_GridCreated(sender, eventArgs) {
                var masterTable = sender.get_masterTableView();
                var selectColumn = masterTable.getColumnByUniqueName("SelectColumnID");
                var headerCheckBox = $(selectColumn.get_element()).find("[type=checkbox]")[0];

                if (headerCheckBox) {
                    headerCheckBox.checked = masterTable.get_selectedItems().length ==
                        masterTable.get_dataItems().length;
                }
            }
    </script>
</telerik:RadScriptBlock>

和网格：

<telerik:RadGrid ID="RadGrid1" runat="server" AllowSorting="True" AllowPaging="True"
                    OnNeedDataSource="RadGrid1NeedDataSource" Width="100%" AllowMultiRowSelection="True" AllowFilteringByColumn="false">
                    <MasterTableView AllowMultiColumnSorting="true" PageSize="100" 
                        DataKeyNames="RFPID, PropCode, Parent, PropName, Address" 
                        AutoGenerateColumns="true" ClientDataKeyNames="RFPID">
                        <Columns>
                            <telerik:GridClientSelectColumn />
                        </Columns>
                        <PagerStyle AlwaysVisible="true"  />
                    </MasterTableView>    
                    <ClientSettings EnableRowHoverStyle="true">
                        <Scrolling AllowScroll="True" UseStaticHeaders="True" SaveScrollPosition="True"></Scrolling>
                       <Selecting AllowRowSelect="true" />
                        <ClientEvents OnRowCreated="RadGrid_RowCreated" OnRowSelected="RadGrid_RowSelected"
                            OnRowDeselected="RadGrid_RowDeselected" OnGridCreated="RadGrid_GridCreated" />
                    </ClientSettings>  
                </telerik:RadGrid>

IE错误发生在这一行：

var headerCheckBox = $（selectColumn.get_element（）） . find（“[type = checkbox]”）[0];