[jQuery] Accessing a JSON property from an unknown variable?

[Nic]

For instance,

var foo = {
"bar": "barVal",
"baz": "bazVal"
}

var fooProp = "bar";

How can I access barVal through fooProp?

I know this isn't exactly jQuery group discussion but I figured since
it was part of a jQuery system I could get away with it. Thanks!