In the Webform Validation module, we have a powerful ally indeed! The basic validation functions that are built into Webform are immensely augmented by the range of possibilities exposed by Webform Validation. The module enables us to specify additional validation rules through a point-and-click interface and, in certain cases, to specify a custom error message for a particular rule.
Let us head on over to the project home page to get the module installed on our site: http://drupal.org/project/webform_validation.
Let's discover how we may utilize the Webform Validation module to extend the range of validations that we may implement on our Webforms.