jq如何动态改变background-position Y轴的值

Question

确保X轴不动，只动态改变Y轴的值
$(window).on("scroll",function(){

   var scrolling = $(this).scrollTop();
  $("#img").css("background-position",0 scrolling);

})

Answer 1

没测试只是感觉你语法首先有问题

 $("#img").css("background-position",'0 '+scrolling);

Answer 2

$("#img").css("background-position",'0 '+scrolling);