That was implicit in my question. We aren't talking about writing purely server side web apps here, and it's reasonable to expect something like client side validation, given that this is meant to be an easy way to do full stack web apps. I think it is but not really easier than other major ones.
> We aren't talking about writing purely server side web apps here
Ok, but note that a big part part of the appeal of htmx is that yes, you work mostly server-side. If your use case absolutely needs client side code, htmx might not be the right fit. (But in many cases you don't need as much client-side Code as you might think at first.)
If you really need client-side, yes, of course you have to script it. If hyperscript is not to your taste, you use a bit of js.