How does GMAIL have a favicon that shows an unread message count? [duplicate]

This question already has answers here: Changing website favicon dynamically (18 answers) Closed 6 years ago.

GMAIL in chrome has a favicon that shows an unread messag开发者_C百科e count. Does anyone know how they do that? Is that them changing images? Or is there a property that allows you to set the number near the favicon?

Thanks

---

I am not 100% certain on how Google accomplishes this however, someone created a UserScript to mimic the functionality. You can view the source code of this script and see how they accomplished it.

http://userscripts.org/scripts/review/39432

EDIT

I'm including this resource since userscripts is no longer around:

http://lab.ejci.net/favico.js/

on github

https://github.com/ejci/favico.js

---

They use different images for counter icons, They have one default favicon and use javascript to update as new email arrives.

e.g.

1. https://mail.google.com/mail/u/1/images/2/unreadcountfavicon/0.png
2. https://mail.google.com/mail/u/1/images/2/unreadcountfavicon/1.png
3. https://mail.google.com/mail/u/1/images/2/unreadcountfavicon/2.png

4. https://mail.google.com/mail/u/1/images/2/unreadcountfavicon/3.png

   

https://mail.google.com/mail/u/1/images/2/unreadcountfavicon/n.png

---

There's no property that sets a number next to the favicon, but you can change it in javascript. Check out this question Changing website favicon dynamically

---

I don't know how Google did it, but the way I did it way:

 $('body').append($('<link rel="icon" type="image/ico" href="http://localhost/myfavicon.ico"/>'))

As needed.

---

I have no clue how they do it, but there's no reason you can't have your /faveicon.ico be responded to by a dynamic server-side script which generates/provides certain content based on information of the user in question.

That said... I don't think most browsers would get the updated Faveicon usually, as most seem to only check it once per session.