Dear fellow limesurveys,
I have a 'UserID' parameter coming from a URL and stored in an Open Text question type (this part it working).
Now, I'd like to validate that each 'UserID' is used only once, so participants will not be able to take the survey more than once.
Can I validate the uniqueness of a value entered in an Open End?
I saw that there is a function in the Expression Manager, but I have no clue on where and how to implement it.
Thank you!
I have a 'UserID' parameter coming from a URL and stored in an Open Text question type (this part it working).
Now, I'd like to validate that each 'UserID' is used only once, so participants will not be able to take the survey more than once.
Can I validate the uniqueness of a value entered in an Open End?
I saw that there is a function in the Expression Manager, but I have no clue on where and how to implement it.
Thank you!