Callback

This time we’ll take a look at two different, JavaScript-y features of Google Analytics and Google Tag Manager. Callback as a concept should be familiar to anyone who’s ever used a programming language. It’s basically a piece of code that is passed as an argument to some function, so that when this second function has completed, the callback is executed.

For web analytics, callbacks are hugely important, since they allow you to impose a firing order for your asynchronous tags. Asynchronous tags, as you might know, abhor order and precision, so sometimes it’s necessary to use a callback to have at least an inkling of predictability in your tag jungle.