Favicons are small square images usually 16×16 pixels which are used by web browsers to show a graphical representation of the site being visited at the left side of the browser's address bar.
Copy and paste the following code into your Userview's settings (i.e. Custom Javascript) and change the path to your favicon.ico accordingly.
Code
// Set the Favicon as the page is loading
$("#favicon").attr("href","/jw/plugin/our.theme.Theme/images/favicon.ico");
$(document).ready(function() {
// Set the Favicon after page load, in case the above doesn't set it properly
$("head").append('<link rel="shortcut icon" href="/jw/plugin/our.theme.Theme/images/favicon.ico"/>');
// This might be required as well in some browsers
$('link[rel="shortcut icon"]').attr('href','/jw/plugin/our.theme.Theme/images/favicon.ico');
}
Credit: Solnet Solutions