Client Script: how to check if a field is visible and the value is "not set"?

Client Script: how to check if a field is visible and the value is "not set"?

In my client script code, I want to find out

1) if a picklist field (called field1) is visible, and

2) if visible, the value of field1 is "not set" (-None- option in the picklist dropdown)

Which functions do I use?

For #1, is there a method like "getVisibility()" for a field? There's a method setVisibility() but I don't see a get-method.

For #2, how do I check if the value is "not set"?