<div class="stage">
  <div class="stage-floor"> </div>  
  <div class="stage-bg"> </div>  
  
  
</div>
body { background: #005f15; }
* { box-sizing: border-box; }

.stage { position: relative; margin: 0 auto; width: 400px; height: 500px; background: #fff; overflow:hidden; }

.stage-floor { position: absolute; bottom: 0; left: 0; width: 2000px; height: 450px;
	background: url(https://wanchen-travel.com/wp-content/uploads/2020/10/stage-floor-bg-1.png) top center no-repeat; z-index: 3 }

.stage-bg { position: absolute; top: 0; left: 0; width: 2000px; height:500px;
	background: url(https://wanchen-travel.com/wp-content/uploads/2020/10/stage-floor-bg-2.png) top center no-repeat; z-index: 2; opacity: 0.6 }

var gameRun;
var speed = 5;
var stageFloor = $(".stage-floor");
var stageBg = $(".stage-bg");

async function start() {
    function floorMov() {
        var nowL = parseInt(stageFloor.css("left").replace("px"), "");
        if (nowL > -1600) {
            stageFloor.css({
                "left": nowL - (speed / 2.5)
            });
        }else{
            stageFloor.css({
                "left": 0
            });
        };
      
      var nowL = parseInt(stageBg.css("left").replace("px"), "");
        if (nowL > -1600) {
            stageBg.css({
                "left": nowL - (speed / 5)
            });
        }else{
            stageBg.css({
                "left":0
            });
        };
      
    };//flooeMov
  await floorMov();
};
gameRun = setInterval(function() {
  start();
}, 50);
    

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js