QS:Preg validation
From LimeSurvey Manual
Validation (using regular expressions) (preg_validation)
Description
This option lets you specify a regular expression with which to validate all parts of a question.
If any question or subquestion value does not meet the validation requirements, the background color of the text entry field will be changed to red so that users can easily see which parts of the question need to be corrected. Thus, you can do on-page validation. In this way you will not need to wait for the user to click on the submit button to validate the respective question.
Valid values
- Any valid regular expression
Example
- Click here to check multiple examples.