Q:

Google Drive API javascript

I'm trying to use the Google drive to list files.
Using the answer in https://stackoverflow.com/a/11280257 I found a problem that I can't discover the reason.
var clientId = '*********.apps.googleusercontent.com';
var apiKey = '##########';
var scopes = 'https://www.googleapis.com/auth/drive';

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) {
    var authorizeButton = document.getElementById('authorize-button');

    if (authResult && !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;
}

function makeApiCall() {  
    gapi.client.load('drive', 'v2', makeRequest);   
}

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

    request.execute(function(resp) {          
        for (i=0; i<resp.items.length; i++) {
            var titulo = resp.items[i].title;
            var fechaUpd = resp.items[i].modifiedDate;
            var userUpd = resp.items[i].lastModifyingUserName;
            var userEmbed = resp.items[i].embedLink;
            var userAltLink = resp.items[i].alternateLink;

            var fileInfo = document.createElement('li');
            fileInfo.appendChild(document.createTextNode('TITLE: ' + titulo + ' - LAST MODIF: ' + fechaUpd + ' - BY: ' + userUpd ));                
            document.getElementById('content').appendChild(fileInfo);
        }
    });    
}

I have this error:
Uncaught TypeError: Cannot read property 'files' of undefined 

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

A:

Using
var request = gapi.client.request({
        'path': '/drive/v2/files',
        'method': 'GET',
        'params': {'maxResults': '1'}
        });

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

resolved the problem!

A:

Code looks OK and you're correctly waiting until gapi.client.load completes. Might just be an error with loading the Drive JS files or some other issue (maybe bad JS file cached?). I modified your example a little bit to run on jsfiddle, take a look at http://jsfiddle.net/Rbg44/4/ for the full example:
HTML:
<button id="authorize-button">Authorize</button>
<div id="content">Files:</div>

JS:
var CLIENT_ID = '...';
var API_KEY = '...';
var SCOPES = '...';

function handleClientLoad() {
    gapi.client.setApiKey(API_KEY);
    window.setTimeout(checkAuth,1);
}

function checkAuth() {
    var options = {
        client_id: CLIENT_ID,
        scope: SCOPES,
        immediate: true
    };
    gapi.auth.authorize(options, handleAuthResult);
}

function handleAuthResult(authResult) {
    var authorizeButton = document.getElementById('authorize-button');

    if (authResult && !authResult.error) {
        authorizeButton.style.visibility = 'hidden';
        makeApiCall();
    } else {
        authorizeButton.style.visibility = '';
        authorizeButton.onclick = handleAuthClick;
    }
}

function handleAuthClick(event) {
    var options = {
        client_id: CLIENT_ID,
        scope: SCOPES,
        immediate: false
    };
    gapi.auth.authorize(options, handleAuthResult);
    return false;
}

function makeApiCall() {  
    gapi.client.load('drive', 'v2', makeRequest);   
}

function makeRequest() {
    var request = gapi.client.drive.files.list({'maxResults': 5 });
    request.execute(function(resp) {          
        for (i=0; i<resp.items.length; i++) {
            var titulo = resp.items[i].title;
            var fechaUpd = resp.items[i].modifiedDate;
            var userUpd = resp.items[i].lastModifyingUserName;
            var userEmbed = resp.items[i].embedLink;
            var userAltLink = resp.items[i].alternateLink;

            var fileInfo = document.createElement('li');
            fileInfo.appendChild(document.createTextNode('TITLE: ' + titulo + 
                ' - LAST MODIF: ' + fechaUpd + ' - BY: ' + userUpd ));                
            document.getElementById('content').appendChild(fileInfo);
        }
    });    
}

$(document).ready(function() {
  $('#authorize-button').on('click', handleAuthClick);
  $.getScript('//apis.google.com/js/api.js', function() {
    gapi.load('auth:client', handleClientLoad);
  });
});

Can you check in your browsers dev tools if there is any sort of issue in the request made when you call gapi.client.load()?

A:

You need to write this :
gapi.client.load('drive', 'v2', null);  

