How to detect when a property is added to a JavaScript object?
<pre><code>var obj = {};
obj.a = 1; // fire event, property "a" added 
</code></pre>

<p>This question is different from <a href="http://stackoverflow.com/questions/1759987/listening-for-variable-changes-in-javascript-or-jquery">this one</a>, where ways to detect when an already declared property is changed, being discussed. </p>
