jsTree not working showing only "loading...." message

<div id="container"></div>
<script src="jquery-1.11.2.js"></script>	
<script>

$(function() {
  $('#container').jstree({
    'core' : {
      'data' : {
        "url" : "//www.jstree.com/fiddle/"
      }
    }
  });
});
</script>
<script src="jstree.min.js"></script>
<style src="style.min.css"></style>