How to get a good score for this index? The advice I can indian email list give you is to use a javascript script to make sure that only when a photo becomes visible to the user it is actually downloaded, not before. Images (and videos) are generally the heaviest elements within a page, but you can apply this deferred loading also for libraries and other content that is not immediately necessary to the user. First Input Delay (FID): How many milliseconds pass before the page responds to a user interaction As soon as the user, after having seen the initial content of the page, after having oriented himself and decided what to do, performs an action (for example, a click), the page itself must be ready to respond.
This index, in other words, measures the response time to the first user interaction. 0 to 100 milliseconds: good 100 to 300 milliseconds: needs some improvement over 300 milliseconds: poor What does this index tell us? That to increase visibility on Google it is not enough to show the initial content of your page to your visitors if then, the loading of other less necessary elements, slows down the response time to a possible click. The page must not only display content quickly, but must also be able to react to the interaction of its visitor just as quickly. To give an example, let's think about a photo gallery: it is certainly important that the first photo appears as quickly as possible, but, at the same time, the user must be able to move on to the next photo without unnecessary waiting.