create category and subcategory menu on the left sidebar I need a category, subcategory and subbactegory based solution for
  example


Project
    Web project
        Project 1
        Project 2
    Desktop project
        Project 1
        Project 2


Project 1 (when i click this then content appear on right side)
Project 2 (when i click this then content appear on right side)


  Basically, when i click on the li page wouldn't be refresh. 1) i click
  on web project then menu expanded Project 1, project 2 appear and if i
  click on project 1 then content related to project 1 appear on the
  right side. Similarly for Project 2 and the subcategory for desktop
  project will be same means i can create subcategory related to desktop
  project.. Like in any category and product relation we need to select
  the category and add the product detail similarly in this
Views Tree would be worth trying.  
Toggling of leaf terms can be handled by javascript.  
To show content, you can declare ajaxified menu callbacks, which simply takes tid as argument and replace a certain section of DOM with the server reponse.