Using ajaxForm with newest jQuery

Using ajaxForm with newest jQuery

Hi! I´m updating my website and my jquery image uploader sadly stop working.. I´m guessing it´s because of the new version of jQuery im  using.. it gives me an error.. 
_____________________________________________________________________________

Uncaught TypeError: $(...).ajaxForm is not a function
_____________________________________________________________________________


This is my code (its working on jQuery 1.7...)


<script type="text/javascript">
$(document).ready(function() {

$('#photoimg').on('change','#photoimg', function()
{ 
$("#preview").html('');
$("#preview").html('<img src="../loader.gif" border="0" width="43" height="11" style="margin-top:70px; margin-bottom:50px; ">');
$("#imageform").ajaxForm(
{
target: '#preview'
}).submit();
});

});


__________________________

Thanks!!!!!