Webform Validation Allow Lowercase Only I have an email field in a webform that will trigger a rule that checks against that field against a user's email.  The issue is, rules is case sensitive so if the webform field had capitals, and the user's email does not, they don't match like they should.

In webform validation, there are two options that should work for me to force the email to only contain lowercase values.

Regular expression, case-sensitive
Validates user-entered text against a case-sensitive regular expression. Works with: email, hidden, number, textarea, textfield.
Regular expression, case-insensitive
Validates user-entered text against a case-insensitive regular expression. Works with: email, hidden, number, textarea, textfield.

Which one of these should I use, and what is the regular expression so that it only disallows capital letters?

Thanks!
Figured it out - Regular Expression, case-sensitive:

Regex Code: [A-Z]

Negate Rule is checked.