function compareError(sender, args) {
var dateStart = $("#<%=txtStartTime.ClientID %>").val().replace(/\-/g, "\/");
var dateEnd = $("#<%=txtEndTime.ClientID %>").val().replace(/\-/g, "\/");
if (dateStart.length > 0 && dateEnd.length > 0) {
if (dateStart > dateEnd) {
args.IsValid = false;
}
else {
args.IsValid = true;
}
}
else {
args.IsValid = true;
}
}
<asp:CustomValidator ID="CustomValidator1" runat="server" ClientValidationFunction="compareError" ForeColor="red" ErrorMessage="截止日期大于起始日期!"></asp:CustomValidator>