head>
<script src="https://apis.google.com/js/client.js"></script>
<script>
function auth() {
var config = {
'client_id': '697275300296.apps.googleusercontent.com',
'scope': 'https://www.googleapis.com/auth/urlshortener'
};
gapi.auth.authorize(config, function() {
console.log('login complete');
console.log(gapi.auth.getToken());
});
}
</script>
</head>
<body>
<button onclick="auth();">Authorize</button>