使用模态窗口不支持gridview翻页！

开发工具vs2012，我使用了模态窗口，在模态窗口中添加了一个GridView，使用gridview自带的翻页时报错：0x80004002 - JavaScript 运行时错误: 不支持此接口
代码如下：      <script type="text/javascript">      
          function ChooseSup() {
              var getVaule = window.showModalDialog("ChooseSupplierPage.aspx", "", 'dialogWidth=' + 900 + 'px;dialogHeight=' + 600 + 'px;help:no;dialogLeft=' + 150 + ';dialogTop=' + 50);
              if (getVaule != null) {
                  var obj = getVaule;
                  document.getElementById("<%=txtSupName.ClientID%>").innerText = obj.name;
                  document.getElementById("<%=hidSupID.ClientID%>").innerText = obj.ID;
              }
          }
    </script>模态窗口前台代码：
  <script type="text/javascript">
         function save() {
             var table = document.getElementById('<%=myGrid.ClientID%>');
             var rowIndex = 0;
             var selected = 0;
             for (var i = 1; i < table.rows.length; i++) {
                 if(table.rows[i].cells[0].getElementsByTagName("input")[0] != null){
                    var input = table.rows[i].cells[0].getElementsByTagName("input")[0].checked;
                    if (input == true) {
                        rowIndex = i;
                        selected++;
                    }
                }
             }
           
             if (selected == 0) {
                 alert("请选择一个供应商！");
                 return false;
             }
             else if (selected > 1) {
                 alert("不能选择多个供应商！");
                 return false;
             }
             else {
                 var obj = new Object();
                 obj.ID = table.rows[rowIndex].cells[1].innerText;
                 obj.name = table.rows[rowIndex].cells[2].innerText;
                 window.returnValue = obj;
                 window.close();
             }
         }
        function closeShow() {
            window.close();
        }
    </script>
翻页事件：
    protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        myGrid.PageIndex = e.NewPageIndex;
        bindGrid();
    }
求解啊！