jsfiddle_vs_real_life

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script>
(function ($) {
  $.salsaform = function () {
    console.log($('#foo'));
  };
})(jQuery);

$(function(){
    $.salsaform();
});

</script>
<div id="foo">
</div>