A Mozilla developer revealed one of the hidden techniques used by Firefox 57, also known as Quantum, to improve page loading times.
Mozilla has already mentioned a number of architectural changes to Firefox Quantum, which seem to have yielded improvements in speed and performance.
But Firefox 57 has another secret that it uses to achieve faster page load: it delays scripts from monitoring domains, such as www.google-analytics.com.
This technique was developed by the engineer of Mozilla Honza Bambas, who calls it “Tailing”. It works by delaying tracking and tracking scripts by opening a page, offering better load times.
The feature is not intended to improve privacy, although it is based on data from the Firefox privacy feature Tracking Protection.
Cutting or to say better, the delay of these scrips simply prevents them from loading, and does not completely disable them.
So we can say that the best performance in loading a page is achieved by changing the browser's priority in site and site tracking requests.
"Requests remain pending as long as there are other requests from the page that are still loading and only for about 6 seconds. The delay only applies to scripts that are added dynamically or async. Tracking images are always delayed. But it is legal by all HTML standards and it is assumed that well-constructed sites will not be affected by their functionality, ”says Bambas.
This technique seems to work well, although in some cases it shows a blank page for a few seconds instead of gradually loading the page. Bambas refers to the Google page, Page-Hiding Snippet which uses as an example where this can happen.
However, as he points out “his intention tailing is to help with performance by delaying something that is not supposed to be visible. "
In addition to all the above, Firefox also runs the project that will display all HTTP pages as unsafe.
Currently it displays warnings on HTTP pages that manage login or financial data.