var handleApi = function(key, callback) {
    $.get('http://www.roblox.com/mobileapi/userinfo', function(data) {
        $.each(objects, function(index, value) {
            if (index == key) {
                callback(value)
            }
        })
    })
}

handleApi("RobuxBalance", function(value) {
    console.log(value) //Nothing is logged, not even 'undefined'
})