[jQuery] $('.class1,.class2').filter(':first') always finds first .class1

[Pyrolupus]

Basically, what I want to do is find the first element that matches
either class1 OR class2.  However, using the syntax from the subject
line:

  var $jqElem = $('.class1,.class2').filter(':first');

$jqElem is always the first element that has class1 (i.e., the first
class specified), rather than the first element for the whole
selector.  E.g., using the above on the following:

  <input type="text" id="elem1" class="class2" />
  <input type="text" id="elem2" class="class1" />

it is getting "elem2."

Am I using the wrong syntax?  I also tried $
('.class1').add('.class2').filter(':first'), but I get the same
result.

Thanks,
Pyro