add a "#" like this:
<a href="#">Add New</a>
Why do you want to toggle the "Add New" link?
The "../add_new.php" indicates that it is one level above the current directory of index.php, is that what you want?
++++++++++++ Round 2 ++++++
It seems that you do not understand the code at all, not to mention javascript, jquery. Suggest you start learning to understand
1.
jQuery Learning Center[
^]
2.
jQuery Tutorial[
^]