This can be achieved purely with JavaScript.
I see the answer I wanted to write has been answered by lynx in comments to the question.
But I'm going to write answer anyway because just like me, people sometimes forget to read the comments.
So, if you just want to get an element's distance (in Pixels) from the top of your screen window, here is what you need to do:
// Fetch the element
var el = document.getElementById("someElement");
use getBoundingClientRect()
// Use the 'top' property of 'getBoundingClientRect()' to get the distance from top
var distanceFromTop = el.getBoundingClientRect().top;
Thats it!
Hope this helps someone :)