Where can I put this “constraint = string-length(.) <= 10”?

[Kal_Lam]

@faqihr, here is a post discussed previously that should show you how to use it:

Building a complex regex constraint to match the entry between an entry made in the previous question and the later question

@finercia_americo, this could be a bit complex but you could do it as outlined in the image shared below: In the survey tab of your xlsform: [Image 1] Data entry screen as seen in Enketo: when a wrong entry is made [Image 2] Data entry screen as seen in Enketo: when a correct entry is made [Image 3] Data entry screen as seen in Enketo: when a wrong entry is made [Image 4] Data entry screen as seen in Enketo: when a correct entry is made [Image 5] Reference xlsform: Regex.xls…