What is $(0) and $(1) used for in jQuery?
<p>While reading the following performance test, I noticed the author used <code>$(0)</code> and <code>$(1)</code>. What is the purpose of this?</p>

<p><a href="http://jsperf.com/scriptjunkie-premature-3">http://jsperf.com/scriptjunkie-premature-3</a></p>

<pre><code>var $a = $(0);

function fn_1() {
 var $a = $(this);
 if ($a.attr("rel") == "foo") {
  $a.addClass("foo");
 }
 else {
  $a.addClass("other");
 }
}

function fn_2() {
 $a.context = $a[0] = this; // fake the collection object
 if ($a.attr("rel") == "foo") {
  $a.addClass("foo");
 }
 else {
  $a.addClass("other");
 }
}
</code></pre>
