function getOffset(e) {
        /*e: Mousemove Event*/
        if (e.target.offsetLeft == undefined) {
            /*firefox only*/
            e.target = target.parentNode;
        }
        var tarPos = getTarPos(e.target);
        var tarMousePos = { x: window.pageXOffset + e.clientX, y: window.pageYOffset + e.clientY     };
        var offset = { offsetX: tarMousePos.x - tarPos.x, offsetY: tarMousePos.y - tarPos.y };
        return offset;
    }
    function getTarPos(el) {
        var page = { x: 0, y: 0 };
        while (el) {
            page.x += el.offsetLeft;
            page.y += el.offsetTop;
            el = el.offsetParent;
        }
        return page;
    }