IE onpropertychange, how to distinguish from real input and set value from JavaScript?
<p>I'd like to listen to user input event in an input bar, so I used <code>onpropertychange</code> in IE:</p>

<pre><code>input.onpropertychange = function(){
    // do something
};
</code></pre>

<p>but if I set the value of that input in JavaScript, the event will be fired too:</p>

<pre><code>input.value = "test";
</code></pre>

<p>How could I distinguish them?</p>
