Problem with adding an additional javascript to a page
<pre><code>function slideSwitch() {
var $active = $('#slideshow DIV.active');

if ( $active.length == 0 ) $active = $('#slideshow DIV:last');

// use this to pull the divs in the order they appear in the markup
var $next =  $active.next().length ? $active.next()
    : $('#slideshow DIV:first');

// uncomment below to pull the divs randomly
// var $sibs  = $active.siblings();
// var rndNum = Math.floor(Math.random() * $sibs.length );
// var $next  = $( $sibs[ rndNum ] );


$active.addClass('last-active');

$next.css({opacity: 0.0})
    .addClass('active')
    .animate({opacity: 1.0}, 1000, function() {
        $active.removeClass('active last-active');
    });
}
</code></pre>

<p>I added this script to a page with additional js, it was working stand alone but now its errors in firebug, newbie, thx for any help...</p>

<pre><code>$(function() {
     setInterval( "slideSwitch()", 5000 );
});
</code></pre>

<p>The error message is:</p>

<pre><code>$ is not defined index.html()()index.html (line 126)
$(function() {
</code></pre>
