JSFiddle - React, Tailwind, and code Playground

HTML

<canvas id="canvas" width="500" height="500" >   
      </canvas>

JavaScript

var canvas = document.getElementById('canvas');		
		var ctx = canvas.getContext('2d');
		var canvasWidth = canvas.width;
		var canvasHeight = canvas.height;
		var refresh = false;
        var y = 0;


window.requestAnimFrame = (function(){
  return  window.requestAnimationFrame       ||
          window.webkitRequestAnimationFrame ||
          window.mozRequestAnimationFrame    ||
          function( callback ){
            window.setTimeout(callback, 1000 / 60);
          };
})();

(function animloop(){
  requestAnimFrame(animloop);
  redraw();
})();


		function redraw() {

            ctx.clearRect(0,0,canvasWidth, canvasHeight);
            ctx.rect(20,y,50,50);
            ctx.fillStyle="red";
            ctx.fill(); 
            y += 2;

		}