Asp自定义验证器在IE-11中不起作用

我正在使用兼容边缘模式将我的应用程序从IE 9迁移到IE 11。asp自定义验证器和必需字段验证器在IE 11中不起作用，但page.isValidat（）始终返回true。但它在IE 9中运行良好。

样本代码：

<asp:DropDownList ID="cboType" onChange="fnInvalid(this,'hidTypeValid');getSelectedValue('cboType','hidliab');changeOptions(document.forms[0].hidliab,document.forms[0].cmbLiability,document.forms[0].hid_liab,document.forms[0].HIDSERLIAB);" runat="server" name="cbotype"AutoPostBack="true"></asp:DropDownList>
                                                            <asp:RequiredFieldValidator ID="VreqvalidateType" runat="server" Display="None" ControlToValidate="cboType" ErrorMessage="-Case Type should not be blank" InitialValue="Choose"></asp:RequiredFieldValidator>
<asp:CustomValidator ClientValidationFunction="fnInvalidSelection" ID="VcustTypeValid"
runat="server" Display="None" ControlToValidate="cboType" ErrorMessage="-Case Type should have valid selection."></asp:CustomValidator>
<asp:CustomValidator ClientValidationFunction="fnTypeFileClass" ID="VcusTypeFile" runat="server" Display="None" ControlToValidate="cboType" ErrorMessage="- Case File Classification should not be empty."></asp:CustomValidator>
 <asp:CustomValidator Enabled="false"ClientValidationFunction="fnTypeCaseHandler"ID="VcusTypeCaseHandler" runat="server" Display="None" ControlToValidate="cboType"ErrorMessage="- Case Handler 1  should not be empty."></asp:CustomValidator>

Javascript：

<pre lang="C#">function fnTypeCaseHandler(sender,args)
    {
    var s = args.Value;
    args.IsValid = true;
        if (s!="K")
        {
        var handler1= document.frmCaseDetails.cmbHandler1.value;
        if (handler1 =="Choose")
        {
            args.IsValid = false;
        }
        }
    return args.IsValid;
    }
function fnTypeFileClass(sender,args)
    {
    var s = args.Value;
    args.IsValid = true;
        if (s!="K")
        {
        var file = document.frmCaseDetails.cmbFileClass.value;
        if (file =="Choose")
        {
            args.IsValid = false;
        }
        }
    return args.IsValid;
    }