How to add validation to custom form?

[wxyu]

Hi, I did not find a way how to validate a custom form. for example limit the max length of text field.

[Rafal_Bain]

There is no out-of-the-box solution to this unfortunately. there are some ideas around this, as this is not unusual thing to request, so you can consider upvoting any of them. 

Alternatively Fusion can provide some validation logic, but this won't be instantenaous as you would like to.

[wxyu]

Thanks @Rafal_Bain yes, this should be a very common requirement But I do not know why they not implement it. Let me check the ideas and vote.

You're right I can use Fusion but that is not what I wanted.