Question about Forms with field dependant fields
I have got to grips with how to make and parse forms with various types of input. But there is one thing that seems simple, but I don't know how to do.
How do you make the availability of one (or a number of) field dependant on another?
For example, I have a single checkbox, followed by a group of checkboxes. If the first one is checked, I want the ones in the group disabled. If the first one is unchecked, all those in the group are available.
So you may select either that first one OR any of the group.
Can this be done with HTML alone, or does it require scripting?