get element position

gistfile1.txt

var elm = document.getElementById("elm");

var getElmPosition = function(elm) {
    var left = 0,
        top = 0;

      while(elm.parentNode) {
        left += elm.offsetLeft;
        top += elm.offsetTop;
        elm = elm.parentNode;
      }
      return {"left" : left, "top" : top};
    }
var elmPos = getElmPosition(elm);