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copied!<p>You've got a few problems:</p> <ol> <li><p><strong><code>Explosion.Loop</code> does not exist</strong>; in normal classical languages, your error would be known as "trying to call an instance method as if it were static." What you could do is instead pass <code>Explosion.prototype.Loop</code> or <code>this.Loop</code>, but that's no good either: JavaScript's <code>this</code> is dynamic and you'll end up trying to get and set properties on <code>window</code> rather than your object.</p> <p>What you need to do is use <code>this.Loop</code>, but make sure the <code>this</code> isn't lost. On newer browsers, that can be done with <code>bind</code><sup>1</sup>:</p> <pre><code>setTimeout(this.Loop.bind(this), 500); </code></pre> <p><sup>1</sup> If they're new enough to support <code>canvas</code>, they probably support <code>bind</code>.</p></li> <li><p><strong><code>setTimeout</code> will only call your function once</strong>; if you want it to be called every half a second rather than only once half a second from now, you'll need to use <code>setInterval</code> instead.</p></li> <li><p><strong>Accessing instance variables as if they were local variables.</strong> In several places (for example, <code>frame</code> in <code>Loop</code>), you're accessing <code>frame</code> like this:</p> <pre><code>frame++; </code></pre> <p>Unfortunately, <code>frame</code> is not a local variable; it's a property of <code>this</code>. Unlike some other languages, you have to explicitly qualify it:</p> <pre><code>this.frame++; </code></pre> <p>As previously mentioned, <code>frame</code> is not the only variable with this problem.</p></li> </ol>

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