difference between function() {} and new function() {}
<p>in this question, I don't want to ask "Function", i want to ask "function" puzzle</p>

<pre><code>&lt;script type="text/javascript"&gt;
    var test = function() {
        alert('a');
    };

    var test1 = new function() {
        alert('b');
    };
&lt;/script&gt;
</code></pre>

<p>why it will pop up the "b"?</p>
