checkbox with treeview

Question

1. (function($)
2. {
3. function Tree() {
4. var $this = this;
6. function treeNodeClick()
7. {
8. $(document).on('click', '.tree li a input[type="checkbox"]', function() {
9. $(this).closest('li').find('ul input[type="checkbox"]').prop('checked', $(this).is(':checked'));
10. }).on('click', '.node-item', function() {
11. var parentNode = $(this).parents('.tree ul');
12. if ($(this).is(':checked')) {
13. parentNode.find('li a .parent').prop('checked', true);
14. } else {
15. var elements = parentNode.find('ul input[type="checkbox"]:checked');
16. if (elements.length == 0) {
17. parentNode.find('li a .parent').prop('checked', false);
18. }
19. }
20. });
21. };
23. $this.init = function() {
24. treeNodeClick();
25. }
26. }
27. $(function() {
28. var self = new Tree();
29. self.init();
30. })
31. }(jQuery))

above jquery used for selecting parent node all child node wil be selected.but my requirement is checking child node parent should be selected ..please give me solutions