Which mobile browsers download favicon.ico and when do they download them?

Question

I've been developing a mobile-biased web app which will have to load quickly on patchy 3G networks. As such I've been very economical with page weight. Now we're putting the finishing touches on the project I'm looking at adding a favicon, largely for the benefit of desktop users. Even though it will only be a few kilobytes I don't want this file to have any negative impact whatsoever on page loading, especially when it won't be much use to the majority of users.

If a user is using iOS safari, the Android Browser or Chrome on Android will the browser actually request the favicon, and if so is the favicon request deprioritized at all to make sure everything else loads first?

Just to clarify I'm talking about the favicon.ico file, not the apple-touch-icon mobile specific icons, which I assume to be loaded on demand (i.e. when you add a page to your home screen)

Answer 1

If you have a favicon.ico file with its declaration in the HTML code, iOS Safari and Android Chrome won't load it (tested on iPad Mini and Galaxy Nexus).

However, if you have Apple Touch icons, they will be loaded immediately by some browsers, not when the page is bookmarked or added to home screen:

• iOS Safari waits for bookmark or add to home screen events. Good.
• Android Chrome loads apple-touch-icon-152x152.png on page load. Arguable.

If network performance is a major issue to you, you should either study the behavior of various devices... or remove all the extra icons.