Google plus API using OAuth.io

HTML

<script src="https://oauth.io/auth/download/latest/oauth.js"></script>
<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/bootstrap/3.0.2/css/bootstrap.min.css">
<script src="http://builds.handlebarsjs.com.s3.amazonaws.com/handlebars-v1.1.2.js"></script>
<input type="button" id="saveBtn" onclick="ShowDriveFileList();" value="Print file list">

CSS

#connect {
    text-align: center;
    padding-top: 15px
}
#connect p {
    color: #AAA;
    margin-top: 20px
}
#res {
    display: none
}
.panel {
    width: 500px;
    margin: 10px auto;
}
#info, .activity-author-info {
    position: relative;
    left: 10px;
    width: calc(100% - 45px);
}
#info p, .activity-author-info p {
    font-size: 0.9em
}
/* spinner by @tobiasahlin: http://tobiasahlin.com/spinkit/ */
 .spinner {
    width: 40px;
    height: 40px;
    position: relative;
    margin: 20px auto;
}
.double-bounce1, .double-bounce2 {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    background-color: #333;
    opacity: 0.6;
    position: absolute;
    top: 0;
    left: 0;
    -webkit-animation: bounce 2.0s infinite ease-in-out;
    animation: bounce 2.0s infinite ease-in-out;
}
.double-bounce2 {
    -webkit-animation-delay: -1.0s;
    animation-delay: -1.0s;
}
@-webkit-keyframes bounce {
    0%, 100% {
        -webkit-transform: scale(0.0)
    }
    50% {
        -webkit-transform: scale(1.0)
    }
}
@keyframes bounce {
    0%, 100% {
        transform: scale(0.0)
    }
    50% {
        transform: scale(1.0)
    }
}

JavaScript

// This only works because we're set to "No wrap - in <head>"
function ShowDriveFileList() {
    var accessToken;
    // Initialize OAuth with our key
    OAuth.initialize('lmGlb8BaftfF4Y5en_c8XYOSq2A');
    
    // Connect to google drive, and print out file list
    OAuth.popup('google_drive').done(function (result) {
        var xmlHttp = null;
        xmlHttp = new XMLHttpRequest();
        xmlHttp.open("GET", "https://www.googleapis.com/drive/v2/files", false);
        xmlHttp.setRequestHeader("Authorization", "Bearer " + result.access_token);
        xmlHttp.send(null);
        alert(xmlHttp.responseText);
    }).fail(function (err) {
        alert(err);
    });;
}