//If the first number is not Zero.
            if (accountNumber && accountNumber.substr(0, 1) != 0) {

                accountNumber = '0' + accountNumber;

                //@source: https://docs.angularjs.org/api/ng/type/ngModel.NgModelController

                //Sets the new account number to the view model - Staged.
                $scope.form_add_payee.accountno.$setViewValue(accountNumber, 'blur');

                // Commit the view model value - committed.
                $scope.form_add_payee.accountno.$commitViewValue();

                // Render the new value to the input field.
                $scope.form_add_payee.accountno.$render();

                // Ignore the validity checking of the field on this model change.
                $scope.form_add_payee.accountno.$setValidity('pattern', true);
            }