Код

by profesor08

HTML

<div class="player">
			<!-- Персонаж -->
		</div>

CSS

.player {
	border: 1px solid black;
	width: 6%;
	height: 17.3%;
	position: absolute;
	bottom: 30%;
	left: 68%;
}

JavaScript

const player = document.querySelector(".player");

const position = {
	x: parseInt(player.offsetLeft),
  y: parseInt(player.offsetTop),
};

const step = 10;

document.body.addEventListener("keydown", function(e) {
	switch(e.keyCode) {
  	case 37: position.x -= step; break;
    case 38: position.y -= step; break;
    case 39: position.x += step; break;
    case 40: position.y += step; break;
  }
  
  player.style.top = `${position.y}px`;
  player.style.left = `${position.x}px`;
});

document.body.addEventListener("keyup", function(e) {
	
});