问题
Because I do not want Facebook to double-count purchases, I store in my database whether I've already triggered a purchase tracking event for a given customer of mine.
And so my code below knows not to run more than once per customer (because my view leaves $('#facebookTrackingPurchaseValue').val() empty if it has already run before).
$(document).ready(function () {
var redirectUrl = decodeURIComponent(decodeURIComponent(handleParams.urlParams.url));//needs to be double-decoded; see FacebookHelper getPixelRedirectPath
var facebookTrackingPurchaseValue = $('#facebookTrackingPurchaseValue').val();
if (facebookTrackingPurchaseValue) {
var isFbPixelLoaded = false;
var fbTrackingInterval = null;
function tryFbTracking() {//Inspired by https://stackoverflow.com/a/44406883/470749
isFbPixelLoaded = true;
try {
var payload = {value: facebookTrackingPurchaseValue, currency: 'USD'};
var shouldTrackOnFb = parseInt(window.shouldTrackOnFb);
if (shouldTrackOnFb) {//This allows env variables to control whether the event fires (since we don't want our local or testing environments to affect Facebook)
fbq('track', 'Purchase', payload);//https://developers.facebook.com/docs/facebook-pixel/implementation/conversion-tracking#standard-events
console.log('fbq event sent.');
}
} catch (err) {
isFbPixelLoaded = false;
}
if (isFbPixelLoaded) {//Wait for FB code to be loaded via GTM... (unfortunately this is a race condition, so we have to poll at an interval)
clearInterval(fbTrackingInterval);
console.log('FBQ tracking worked!');
sleep(200).then(() => {//This 'sleep' might be superfluous.
redirectNow(redirectUrl);
});
}
}
fbTrackingInterval = setInterval(function () {
tryFbTracking();
}, 100);
} else {
redirectNow(redirectUrl);
}
});
However, few of the purchases are getting tracked at all.
I don't see nearly as many Purchase events in https://business.facebook.com/events_manager/pixel/events as I have customers (in a given time period).
Does fbq('track', 'Purchase', payload); only work if the visitor is logged-in to Facebook (on that same device at that same moment)?
If so, how can my javascript code (or PHP) detect that the visitor is not currently logged-in to Facebook (in which case I'll set my code not to fire the fbq tracking and instead wait until a future page visit, at which point it will again check whether the visitor is logged-in to FB this time, and could fire the tracking event)?
来源：https://stackoverflow.com/questions/57793493/why-is-my-facebook-purchase-tracking-via-javascript-working-inconsistently