Hi,
apologies if this has a really simple answer. I thought that by simply setting a question to mandatory, the system would perform a first attempt to validate the page client side / in the browser itself. However, if I do not answer a mandatory question, it seems that the validation is performed only server side.

Is there any workaround for this? I think the usability would be improved by a great deal by avoiding unnecessary round trips.

No, there is no core client side validation.

It could be added but the details of any script would depend on the question type, etc.

SkelVanilla can do it with option,

For mandatory and for all restriction system ! it use all html5 input attribute . In general it work good.

See extensions.sondages.pro/themes-and-templ...html#Custom-validity

Test survey

But there are an issue whan validating client side : if browser broke : data is not saved. Then if you have a lot of question by page : better let's do it only via PHP