Why can I not successively increment a variable within a function?
<p>I'm trying to add 10 over and over for every invocation of <code>d</code>. It stays 20 every time, why?</p>

<pre><code>function d() {
    var c = [10];
    c[0] += 10;
    alert(c[0]); // always 20
}
d(); d(); d(); // supposed to be 20, 30, 40...
</code></pre>
