Is complex field validation possible with WebForm?

Question

WebForm is a very nicely done module, but (at least at first glance) it seems to lack some things that I expect to need.

Specifically, I'd like a way to specify more complex field requirements than just a boolean. For instance, what if I have a form with an e-mail address field and a telephone field, and I want the user to be required to enter at least one of the two. In other words, if they enter an e-mail address, they don't need to enter a phone number; and if they enter a phone number, they don't need to enter an e-mail address.

Is this possible with WebForm?

Answer 1

Try using the WebForm Validation module.

The following validation rules are currently included:

• Numeric values (optionally specify min and / or max value)
• Minimum length
• Maximum length
• Minimum number of words
• Maximum number of words
• Equal values on multiple fields
• Unique values on multiple fields
• Specific value
• Require at least one of two fields
• Require at least one of several fields
• Minimum number of selections required
• Maximum number of selections allowed
• Exact number of selections required
• Plain text (disallow tags)
• Regular expression
• Must be empty (Anti-Spam: Hide with CSS)
• Words blacklist
• Must match a username

Answer 2

If your validation logic is complex it might be better to do that through a custom module.

There are three ways:

1. Regular hook_form_alter() and adding your validation callback to the $form['#validate'] array.

2. Implement hook_webform_validation_validators().

3. Implement hook_webform_validation_validate().

See this article for more information about 2. and 3.