Protected void txtBelowPercentage_TextChanged (object sender, EventArgs e) { if (Convert.ToDecimal(txtAbovePer.Text) == 0) { decimal Amount = Convert.ToDecimal(txtEsAmount.Text == string.Empty ? "0" : txtEsAmount.Text); decimal abovebelow = Convert.ToDecimal(txtBelowPer.Text == string.Empty ? "0" : txtBelowPerc.Text); decimal abovebelowvalue = EsAmount * (abovebelow / 100); decimal TenderAmount = EsAmount + abovebelowvalue; txtTend...