just move+falling-balls animations

simple-space-ship.html

<!-- www.alash3al.xyz -->
<style>
	* {
		margin: 0;
		padding: 0;
	}
	body {
		background: #000;
		overflow: hidden;
	}
	#ship {
		width: 80px;
		height: 80px;
		position: absolute;
		right: 200px;
		bottom: 0;
	}
</style>
<script>		
	var H = window.innerHeight
	var W = window.innerWidth
	var BALLS = []
	var COLORS = ["red", "green", "yellowgreen", "blue", "black", "white", "greenyellow", "orange", "maroon"]

	function makeBall(id) {
		ball = document.createElement("div")
		ball.id = "ball-" + id
		ball.style.background = COLORS[Math.round(COLORS.length * Math.random())]
		ball.style.borderRadius = "50%"
		ball.style.display = "inline-block"
		ball.style.position = "absolute"
		ball.style.margin = "auto"
		ball.style.top = (H * Math.random()) + "px"
		ball.style.left = (W * Math.random()) + "px"
		ball.style.width = "5px"
		ball.style.height = "5px"
		return ball
	}
	function drawBalls(count) {
		for ( i = 0; i < count; i ++ ) {
			id = i + 1
			ball = makeBall(id)
			BALLS.push(id)
			document.body.appendChild(ball)
		}
	}
	function moveBalls() {
		for ( var k in BALLS ) {
			id = BALLS[k]
			ball = document.getElementById("ball-" + id)
			ball.style.top = (H * Math.random()) + "px"
			ball.style.left = (W * Math.random()) + "px"
			ball.style.width = ball.style.height = (8 * Math.random()) + "px"
		}
	}
	function mv(obj, x, y) {
		right = parseInt(obj.style.right || 200)
		bottom = parseInt(obj.style.bottom || 0)
		if ( (x != "undefined") && (obj.offsetLeft >= 0) && (right >= 0) ) {
			if ( ((obj.offsetLeft - x) >= 0) && ((right + x) >= 0) ) {
				obj.style.right = (right + x) + "px"
			}
		}
		if ( (y != "undefined") && (obj.offsetTop >= 0) && (bottom >= 0) ) {
			if ( ((obj.offsetTop - y) >= 0) && ((bottom + y) >= 0) ) {
				obj.style.bottom = (bottom + y) + "px"
			}
		}
	}

	window.onload = function(){
		// draw white balls
		drawBalls(100)
		// move the generated balls "and change some attrs"
		setInterval(moveBalls, 1500)
		// handle keyboard buttons
		window.onkeydown = function(e){
			ship = document.getElementById("ship")
			//console.log(e.keyCode)
			switch(e.keyCode) {
				// right
				case 39:
					mv(ship, -5)
					return false
				// left
				case 37:
					mv(ship, 5)
					return false
				// top
				case 38:
					mv(ship, undefined, 5)
					return false
				// bottom
				case 40:
					mv(ship, undefined, -5)
					return false
			}
		}
	}
</script>
<img id="ship" src="http://icons.iconarchive.com/icons/everaldo/crystal-clear/128/App-launch-spaceship-icon.png">