Google Analytics空客户端ID

Question

Why sometimes I get empty client ID ? For example for ~90% of my page visitors Google Analytics set clientID normally, I'm checking it by:

ga(function(tracker) {
  clientId = tracker.get('clientId');
});

and it returns some xxxxx.xxxxx number. But for ~10% of visitors it return empty value. why?

Im checking if ga is loaded by:

if (typeof ga === 'function')

And it seems that its ok. My whole function looks like:

function check_ga() {
  var clientId = "";
  if (typeof ga === 'function') {
    ga(function(tracker) {
      clientId = tracker.get('clientId');
    });

    if(clientId == "") 
    {
      ga('create', 'UA-XXXXXX-X', 'auto'); //trying to create new ga object
      ga(function(tracker) {
        clientId = tracker.get('clientId');
      });
    }

    if(clientId == "") 
    {
      clientId = "No CID";
    }
  } else {
    clientId = "GA Not loaded";
  }
  return clientId;
}

And time to time I get "No CID" value. Why?? As you see, im trying to create new GA object, but it is not working also.

Answer 1

When invoking the ga command queue, functions that are passed in are only executed as soon as the analytics library is completely loaded. In your code, you queue up your callback function to evaluate the client id and assign it to your variable, but when you determine if it is empty or not, it is in fact still empty because the analytics library still has not completely loaded, thus resulting in the "No CID" being assigned.

Cf. GA command queue