jquery check variable values

In Jquery I have the following 4 variables.

    var add
     var city
     var state
     var zip
 

I need to check to see that any one of the above have a value.
If none have a value that is OK.
If all of them have a value that is OK.

Just need to check that at least one of them do not have a value.
Not sure what is the most efficient way of doing this.

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