Not able to invoke jquey Ajax method for fileupload input value

I am trying to invoke the serverside method from the jquery. It is working fine in FireFox but not in IE8 and IE9.

Please find the below code sample :
<div>
<asp:FileUpload ID="flAppIcon" runat="server" onchange="GetFileSize();"/>
<asp:HiddenField ID="_hdnAppIcon" runat="server" Value="0" />
</div>

<script type="text/javascript" language="javascript">
function GetFileSize() {
var PageURL = '<%= ResolveUrl("~/WebForm16.aspx") %>'
var test = ($('#<%=flAppIcon.ClientID%>').val()).toString();
$("#<%=_hdnAppIcon.ClientID%>").val(test);
alert($("#<%=_hdnAppIcon.ClientID%>").val());
$.ajax({
type: "POST",
url: PageURL + '/GetFileSizeDetails',
data: '{file: "' + $("#<%=_hdnAppIcon.ClientID%>")[0].value + '"}',
contentType: "application/json; charset=utf-8",
dataType: "json",
success: OnSuccess,
failure: function (response) {
alert(response.d);
}
});
}
function OnSuccess(response) {
alert(response.d);
}
</script>
[System.Web.Services.WebMethod]
public static string GetFileSizeDetails(string file)
{
return "100";
}
Can anyone help me to know the root cause of this issue.

Thanks & Regards,
Santosh Kumar Patro

santosh kumar patro