Making an option appear depending on dropdown selection

I have seen this somewhere before but can't remember where.

I am making a form for booking seats for some events. There will be two Fields i.e. a events dropdown list and a date field that will be populated with a date and readonly.

If Event1 is selected then the date field should appear with the one pre-populated date and if Event2 then with a different date.

Hi abasel,

A touch of JavaScript is needed, there is at least one example in the FAQs that could be adapted for this.

Bob

Thanks :-)