Here I am
<!DOCTYPE html>
<canvas id="canvas" width="500" height="500"></canvas>
<script>
canvas = document.getElementById('canvas');
c = canvas.getContext('2d');
c.clear = function() {this.clearRect(0,0,500,500);};
function wait(fn) {window.setTimeout(fn, 250); }
function repeat(fn) {
if (window.requestAnimationFrame) {
var advance = function() {fn(); requestAnimationFrame(advance);};
requestAnimationFrame(advance);
} else window.setInterval(fn, 50);
}
var dx = 0, dy = 0, mousex = 0, mousey=0, mouseclicks = 0;
document.onkeydown = function(e) {
var key = e.keyCode;
if (key == 37) dx=-1;
else if (key == 38) dy=-1;
else if (key == 39) dx=1;
else if (key == 40) dy=1; else return true;
return false;
};
document.onkeyup = function(e) {
var key = e.keyCode;
if (key == 37 || key == 39) dx=0;
else if (key == 38 || key == 40) dy=0;
else return true;
return false;
};
canvas.onmousemove = function(e) {
var rect = canvas.getBoundingClientRect();
mousex = e.clientX - rect.left;
mousey = e.clientY - rect.top;
};
canvas.onmousedown = function(e) {mouseclicks++;};
</script>