authorization code generate different type of access token
<p>why this given code generate different types of access token for same user id. i want to get the same access token each time for a user. this code is used for autherization, and to get the acess token and for get list file in google drive. tell me the detailed information about this code.</p>

<pre><code>&lt;html&gt;
&lt;head&gt;
    &lt;meta charset='utf-8' /&gt;
    &lt;style&gt;
        p {         
            font-family: Tahoma;
        }
    &lt;/style&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;!--Add a button for the user to click to initiate auth sequence --&gt;
    &lt;button id="authorize-button" style="visibility: hidden"&gt;Authorize&lt;/button&gt;
    &lt;script type="text/javascript"&gt;
        var clientId = '914579210572.apps.googleusercontent.com';
        var apiKey = 'AIzaSyB9bVKr6OrPe97vHVOqlzsyKQcq6cmF2tg';
        // To enter one or more authentication scopes, refer to the documentation for the API.
        var scopes = 'https://www.googleapis.com/auth/drive https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile';

        // Use a button to handle authentication the first time.
        function handleClientLoad() {
            gapi.client.setApiKey(apiKey);
            window.setTimeout(checkAuth, 1);
        }

        function checkAuth() {
            gapi.auth.authorize({ client_id: clientId, scope: scopes, immediate: true }, handleAuthResult);
        }

        function handleAuthResult(authResult) {
            debugger
            var authorizeButton = document.getElementById('authorize-button');
            if (authResult &amp;&amp; !authResult.error) {
                authorizeButton.style.visibility = 'hidden';
                makeApiCall();
            } else {
                authorizeButton.style.visibility = '';
                authorizeButton.onclick = handleAuthClick;
            }
        }

//        function handleAuthClick(event) {
//        
//            gapi.auth.authorize({ client_id: clientId, scope: scopes, immediate: false }, handleAuthResult);
//            return false;
//        }

        // Load the API and make an API call.  Display the results on the screen.
        function makeApiCall() {
            gapi.client.load('drive', 'v2', function () {

                var request = gapi.client.drive.files.list({ 'maxResults': 5 });

                request.execute(function (resp) {
                    for (i = 0; i &lt; resp.items.length; i++) {
                        var titulo = resp.items[i].title;
                        var fechaUpd = resp.items[i].modifiedDate;
                        var userUpd = resp.items[i].lastModifyingUserName;

                        var fileInfo = document.createElement('li');
                        fileInfo.appendChild(document.createTextNode('TITLE: ' + titulo + ' - LAST MODIF: ' + fechaUpd + ' - BY: ' + userUpd));
                        document.getElementById('content').appendChild(fileInfo);
                    }
                });
            });
        }
    &lt;/script&gt;
    &lt;script src="https://www.googleapis.com/drive/v2/files"&gt;&lt;/script&gt; 
  &lt;script src="https://apis.google.com/js/client.js?onload=handleClientLoad"&gt;&lt;/script&gt;    
    &lt;p&gt;&lt;b&gt;These are 5 files from your GDrive :)&lt;/b&gt;&lt;/p&gt;
    &lt;div id="content"&gt;&lt;/div&gt;
  &lt;/body&gt;
&lt;/html&gt;
</code></pre>
