gistfile1.js

function getPosition(el) {
    if (el.getBoundingClientRect) {
        //They have getBoundingClientRect
        var box = el.getBoundingClientRect();
        if (typeof arguments.callee.offset != "number") {
            var temp = document.createElement("div");
            temp.style.cssText = "position:absolute;top:0;left:0";
            document.body.appendChild(temp);
            arguments.callee.offset = -temp.getBoundingClientRect().top;
            document.body.removeChild(temp);
            temp = null;
        }
    } else {
        //Other Browsers here..
    }
}