gistfile1.js

gapi.client.load('gmail', 'v1', function(){
			  listThreads('me', function(dataResult){
				  $.each(dataResult, function(i, item){
					  getThreads('me', item.id, function(dataMessage){
						  var temp = dataMessage.messages[0].payload.headers;
						  $.each(temp, function(j, dataItem){
							  if(dataItem.name == 'From'){
								  console.log(dataItem.value);
							  }
						  });
					  });
				  });
			  });

add the getThreads() method as

function getThread(userId, threadId, callback) { var request = gapi.client.gmail.users.threads.get({ 'userId': userId, 'id': threadId }); request.execute(callback); }

I am using your getThread() function and now getting that dataMessage.messages is undefined.

gapi.client.load('gmail', 'v1', function(){
     listThreads('me', function(dataResult){
             $.each(dataResult, function(i, item){
                 getThread('me', item.id, function(dataMessage){
                     var temp = dataMessage.messages[0].payload.headers;
                      $.each(temp, function(j, dataItem){
                          if(dataItem.name == 'From'){
                           console.log(dataItem.value);
                      }  
                     });
                });
            });
        });
    });

Hi theirf, have you found the solution for your Gmail Api problem?