David Lanham 新 iOS 遊戲 “Hatch” 的官網視頻中，最後小寵物從畫面跑進網頁的效果是如何實現的？

<code class="language-text">var scale = 1;
var baseHeight = 544 * scale;
var baseWidth = 602 * scale;
var eachFrame = 15;

var canvas = $('<canvas id="canvas"></canvas>').css({
	'position': 'fixed',
	'zIndex': 9999,
	'bottom': '0',
	'overflow': 'hidden',
}).attr({
	'width': baseWidth,
	'height': baseHeight,
});

$('body').append(canvas);


var frameCnt = 0;
var context = canvas[0].getContext('2d');

function animate(isReset) {
	if (isReset) {
		frameCnt = 0;
	};
	// clear
	context.clearRect(0, 0, baseWidth, baseHeight);
	// draw stuff
	context.drawImage(imageObjs[parseInt(frameCnt / eachFrame)], (frameCnt % eachFrame) * baseWidth, 0, baseWidth, baseHeight, 0, 0, baseWidth, baseHeight);
	frameCnt++;
	// request new frame
	if (frameCnt </code>