High performance favicons (updated 2012-04-16)Date: 15 Mar 2012
Author: Erik Dubbelboer
For my company we have an ad-server which handles hundreds of connections per second. Many of those are HTML iframes for ads. It doesn’t really make sense for those pages to have a favicon but we noticed that many browses still request favicon.ico. This only ads load to our already busy server so we place the following code in our iframe HTML:
<link rel="shortcut icon" href="data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==">
This is the smalles possible image in a data url. A 1x1 gif. Even though data url’s aren’t support in IE versions before 9 we hardly notice any requests for favicon.ico anymore (Maybe IE doesn’t request favicon’s for iframes?).
Some days ago I had the idea for a even smaller favicon, namely
<link rel="shortcut icon" href="about:blank">
I have tested all the options for a couple of days and collected the following data:
No favicon in the html
6752 requests per hour.
- 48% Chrome
- 42% Firefox
- 10% IE
252 requests per hour.
- 50% Firefox
- 22% Opera
- 15% IE
- 13% Google Desktop
106 requests per hour.
- 100% IE