Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);

function EndRequestHandler(sender, args) {
    if (args.get_error() != undefined) {
        var errorMessagePrefix = "Oops! Something went wrong and server couldn't process your request. "
                               + "Please try again later.\n\nIf this error will happen again, please "
                               + "contact support at support@nor-calmoving.com or use our feedback form (Help -> Contact Support).\n\nAdditional information:\n";
        var errorMessage;
        if (args.get_response().get_statusCode() == '200') {
            errorMessage = args.get_error().message;

            errorMessage = errorMessage.replace("Sys.WebForms.PageRequestManagerParserErrorException: ", errorMessagePrefix);
            errorMessage = errorMessage.replace("Sys.WebForms.PageRequestManagerServerErrorException: ", errorMessagePrefix);
            errorMessage = errorMessage.replace("Sys.WebForms.PageRequestManagerTimeoutException: ", errorMessagePrefix);
        }
        else {
            // Error occurred somewhere other than the server page.
            errorMessage = errorMessagePrefix + 'An unspecified error occurred (' + args.get_response().get_statusCode() + ').';
        }
        
        args.set_errorHandled(true);

        if (args.get_response().get_statusCode() != '0') {
            alert(errorMessage);
        }
    }
}