Effect of x = +x in JavaScript
<p>Going though the <a href="http://asmjs.org/spec/latest/">asm.js</a> documentation I've observed this strange (to me at least, quite new to JS) snippet all over the sample code:</p>

<pre><code>function test(x) {
    x = +x; // THIS
    ...
    return +(x*y);
}
</code></pre>

<p>What is the purpose of the <code>+</code> on the first line?</p>
