fix(vakata#2755) : set the aria-exepended attribute on the link element

src/jstree.js

@@ -84,7 +84,7 @@
  idregex : /[\\:&!^|()\[\]<>@*'+~#";.,=\- \/${}%?`]/g,
  root : '#'
  };
- 
+
  /**
  * creates a jstree instance
  * @name $.jstree.create(el [, options])
@@ -454,7 +454,7 @@
  */
  restore_focus : true,
  /**
- * Force to compute and set "aria-setsize" and "aria-posinset" explicitly for each treeitem. 
+ * Force to compute and set "aria-setsize" and "aria-posinset" explicitly for each treeitem.
  * Some browsers may compute incorrect elements position and produce wrong announcements for screen readers. Defaults to `false`
  * @name $.jstree.defaults.core.compute_elements_positions
  */
@@ -2722,7 +2722,7 @@
  if(!animation) {
  this.trigger('before_open', { "node" : obj });
  d[0].className = d[0].className.replace('jstree-closed', 'jstree-open');
- d[0].childNodes[1].setAttribute("aria-expanded", true);
+ d.children('.jstree-anchor').attr("aria-expanded", true);
  }
  else {
  this.trigger('before_open', { "node" : obj });
@@ -4996,7 +4996,7 @@
  return d;
  };
  $.vakata.trim = function (text) {
- return String.prototype.trim ? 
+ return String.prototype.trim ?
  String.prototype.trim.call(text.toString()) :
  text.toString().replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, '');
  };