var note = document.getElementsByName('Note')[0];
var screenPosition = note.getBoundingClientRect();
The ClientRect returned by getBoundingClientRect() has values for .top, .left, .right, .bottom, .width, and .height.
These are pixel positions on the visible window; as you scroll the page the .top and .bottom values will change, and may even become negative as the item scrolls off the top of the view.
Note that—unlike the solution accumulating offsetLeft/offsetTop—this solution properly accounts for borders and padding on the body and html elements in all browsers (Firefox).
See this test case: http://jsfiddle.net/QxYDe/4/ (scroll the page and watch the values change).
Also supported by Internet Explorer.