Get the current position of an element relative to the top of the viewport

currentScrollPos.js

(function ($) {
    $.fn.currentScrollPos = function () {
        var obj = this.offset().top;
        obj = obj - window.pageYOffset;
        return obj;
    }
})(jQuery);

$(window).scroll(function () {
    console.log($('#your-element').currentScrollPos());
}