Does not redirect page after UploadComplete in AsyncFileUpload c#

I am using Ajax AsyncFileUpload in asp.net. It is working fine in uploading image but don't know why it is redirecting to same page with some querystring OnUploadComplete. I don't want to reload page. How to solve this ?

My Code is as below:

function uploadComplete() {
    document.getElementById('<%=lblPhotoUpload.ClientID %>').innerHTML = "Quiz Image Uploaded Successfully.";$("#UploadQuizImageProcess").hide();
}

function uploadError() {
     document.getElementById('<%=lblPhotoUpload.ClientID %>').innerHTML = "File Upload Failed.";$("#UploadQuizImageProcess").hide();
}
function uploadQuizImageStart() {$("#UploadQuizImageProcess").show();
}<asp:AsyncFileUpload ID="fuPhoto" runat="server" UploadingBackColor="#779ED3" CompleteBackColor="#179406" ThrobberID="imgLoad" OnUploadedComplete="QuizImageUploadComplete" OnClientUploadStarted="uploadQuizImageStart" OnClientUploadComplete="uploadComplete" OnClientUploadError="uploadError" UploaderStyle="Traditional" /><span id="UploadQuizImageProcess" style="display: none"><img src="../images/uploading.gif" alt="Upload" /></span><asp:Label ID="lblPhotoUpload" runat="server" CssClass="lbler"></asp:Label>

protected void QuizImageUploadComplete(object sender, AsyncFileUploadEventArgs e)
    {
        if (fuPhoto.HasFile)
        {
            string filename = "";
            filename = "quiz" + ".jpg";

            // Save Image
        }
    }