hi deepakkumarjoshi,
AjaxUploader need to transfer the upload files to the server, so the postback is necessary.
If you just want to prevent it, you can try the code below
<script>
function CuteWebUI_AjaxUploader_OnPostback()
{
return false;
}
</script>
If you want to submit the page after all your logic, please use the start uploading manually example. Below is the demo link
Regards,
Ken