Doesn't work with Chrome 78 (most of the time)

[turt2live]

The first badge update goes through fine, but then updates are only applied when the user is looking at the page. This seems to be a Chrome change because it works fine in earlier versions of Chrome, but the fix for the time being is to trigger the update twice.

[stekie]

The canvas context which receives the draw calls doesn't update the canvas display immediately in new chrome versions when the page is not visible.
It is however updated after the next tick in the event loop. You, therefore, can change the "link.setIcon" function in the source code to:

link.setIcon = function (canvas) {
setTimeout(function() {
var url = canvas.toDataURL('image/png');
link.setIconSrc(url);
}, 0);
};