title: jquery animate image start at wrong spot after scroll
body: <p>guys I'm using a animate which  the image fly to my cart icon position after clicking the button. Although I can let image fly to right place after scroll ,but
  there's  distance between my button and start spot. here's the plugin I refer <a href="http://www.jqueryscript.net/other/Simple-Shopping-Cart-Plugin-With-jQuery-Bootstrap-mycart.html" rel="nofollow noreferrer">http://www.jqueryscript.net/other/Simple-Shopping-Cart-Plugin-With-jQuery-Bootstrap-mycart.html</a></p>
  
  <p>My code is below . pleaese give me some ideas .thank you</p>
  
  <pre><code>    var goToCartIcon = function($addTocartBtn){
                var $cartIcon = $(".my-cart-icon");
                var $image = $('&lt;img width="30px" height="30px" src="' + $addTocartBtn.data("image") + '"/&gt;').css({"position": "fixed", "z-index": "999"});
                $addTocartBtn.prepend($image);
                var position = $cartIcon.offset();
                var w = $(window);
  
                $image.animate({
                  top: position.top-w.scrollTop(),
                  left: position.left-w.scrollLeft()
                }, 500 , "linear", function() {
                  $image.remove();
                });
              }
  </code></pre>