Where is the documentation for the built-in JavaScript function toString?
<p>I was looking through the jQuery code and found that isArray is implemented using the built-in function toString.  I cannot find the documentation for this function on MDC.  Does the doc exist?  What does this function do?</p>

<pre><code>isArray: function( obj ) {
             return toString.call(obj) === "[object Array]";
         },
</code></pre>
