Changing website favicon dynamically

Question

I have a web application that\'s branded according to the user that\'s currently logged in. I\'d like to change the favicon of the page to be the logo of the private label,

Answer 1

Why not?

(function() {
    var link = document.querySelector("link[rel*='icon']") || document.createElement('link');
    link.type = 'image/x-icon';
    link.rel = 'shortcut icon';
    link.href = 'http://www.stackoverflow.com/favicon.ico';
    document.getElementsByTagName('head')[0].appendChild(link);
})();

Firefox should be cool with it.

edited to properly overwrite existing icons