Hello Marek,

Thanks for reaching out to us.

By default, there is no validation in the background, but i will forward this to the developers so they can provide a script as a workaround. I suppose this is related to the Step By Step Booking form?

Thanks. Looking forward to your reply.

Hello Marek,

You can add this script to the page where the booking form is located:

<script>     
window.ameliaActions = {
  customValidation: function (success = null, error = null, data) { 
   const customValidator = (rule, value, callback) => {
        let regex = /\d/g;
        let matches = value.match(regex);
      if (matches.length !== 12 && matches.length !== 9) {
        callback(new Error())
      } else {
        callback()
      }
    }
  // this example is for phone input field
if (data.rules.phone.length < 2) {
data.rules.phone.push({message: 'CUSTOM MESSAGE', validator: customValidator})
}     
   }, 
} 
</script>

You can change 'CUSTOM MESSAGE' to the message that you want to display.

I hope it helps. Please, let us know if it works.