js interview questions

1. Write a function that will create and return a simple
write-once data object. The object should have a set(key,
val) and get(key). Setting a key a second time throws an
error. The internal state should not be visible to the
consumer.
1a. Use ES5.
1b. Don't use ES5, so that it works in IE.

2. You have a web form with two options, "yes" and "no". Only
one can be selected at a time. If the user selects "no", then
you should show them a warning. if they select "yes", then
the warning should go away. Explain the various choices.
2a. The warning is created on the server