When are JavaScript objects destroyed?
<p>In C++ I can define a constructor and destructor explicitly, and then cout &lt;&lt; "C or D Called" from with in the constructor/destructor function, to know exactly where.</p>

<p>However in JavaScript how do I know when an object is destructed.  The example below is the case that concerns me.</p>

<p>I'm calling an internal function on a timeout and I'm wondering if the object stays alive as long as the timer is running, waiting to call next again.</p>

<p><strong>User Click calls Control</strong></p>

<pre><code>// Calls  Control
</code></pre>

<p><strong>Control calls Message</strong></p>

<pre><code>var message_object = new Message( response_element );
</code></pre>

<p><strong>Message calls Effects</strong></p>

<pre><code>new Effects().fade( this.element, 'down', 4000 );
message_object.display( 'empty' );
</code></pre>

<p><strong>Effects</strong></p>

<pre><code>/**
 *Effects - build out as needed
 *  element - holds the element to fade
 *  direction - determines which way to fade the element
 *  max_time - length of the fade
 */

var Effects = function(  ) 
{
    this.fade = function( element, direction, max_time ) 
    {
        element.elapsed = 0;
        clearTimeout( element.timeout_id );
        function next() 
        {
            element.elapsed += 10;
            if ( direction === 'up' )
            {
                element.style.opacity = element.elapsed / max_time;
            }
            else if ( direction === 'down' )
            {
                element.style.opacity = ( max_time - element.elapsed ) / max_time;
            }
            if ( element.elapsed &lt;= max_time ) 
            {
                element.timeout_id = setTimeout( next, 10 );
            }
        }
        next();
    }
};
</code></pre>
