Google Analytics | Get GA Client ID cookie data and other GA data on Gravity Form submit via hidden fields

gravity-forms-google-analytics-client-id-field.js

// get GA Client ID when using analytics.js
// set the tracker data via the ready callback
// https://developers.google.com/analytics/devguides/collection/analyticsjs/cookies-user-id#getting_the_client_id_from_the_cookie
// more info: https://developers.google.com/analytics/devguides/collection/analyticsjs/accessing-trackers#getting_data_stored_on_a_tracker
// fields we can get with a tracker: https://developers.google.com/analytics/devguides/collection/analyticsjs/field-reference
// helpers: https://www.simoahava.com/analytics/universal-analytics-plugins-explained/
// helpers: https://hevodata.com/learn/google-analytics-and-salesforce/

// check to see if the ID exists first
var gform_6_exists = document.getElementById('gform_6');

// if that variable exists, then continue...
if(gform_6_exists) {

	// keep an eye on this form and trigger on form submit
	gform_6_exists.addEventListener('submit', function(event) {

		// uses ga object methods inside a readyCallback as they're guaranteed to be available.
		ga(function() {

			// get all the Google Analytics tracker data, so we can then specify which ones we want to use (by getting list of first elements in the array)
			var tracker = ga.getAll()[0];

			var clientId = tracker.get('clientId');
			document.getElementById('input_6_6').value = clientId;

			var screenResolution = tracker.get('screenResolution');
			document.getElementById('input_6_7').value = screenResolution;

			var viewportSize = tracker.get('viewportSize');
			document.getElementById('input_6_8').value = viewportSize;

		});

	});

}