Hi,
you have to declare the object that holds the desired date first.
Then you can read the desired date the following way:
var repTable = {
a : {a1: 111, a2: 112},
b : {b1: 221, b2: 222}
},
repA = repTable['a']['a1'],
repB = repTable['b']['b2'];
xfa.host.messageBox(repA.toString());
Hope this helps.