Display a visual at a certain position in the browser with javascript/jquery : is it possible for me to display some sort of visual at a certain position in the browser(firefox)? Let's say I have these offsets {left: 336, top: 378} which I am calculating dynamically, and I want to display a small line of some sort (either an `<hr>` or an image, depending on what is possible). Is this even possible? Any help is greatly appreciated. Ideally I don't want to intefere with the markup at all, I'd rather have some sort of overlay.