Smarty templates display

[Sakoure]

I have 2 template files, department_list.tpl and category_list.tpl

How can I have the categories for each department to display right under the department name, when clicked?

Your help will be greatly appreciated.

{* departments_list.tpl *}
{load_presentation_object filename="departments_list" assign="obj"}
{* Start departments list *}
<div class="box">
  <p class="box-title">Choose a Department</p>
  <ul>
  {* Loop through the list of departments *}
  {section name=i loop=$obj->mDepartments}
    {assign var=selected value=""}
    {* Verify if the department is selected to decide what CSS style
       to use *}
    {if ($obj->mSelectedDepartment ==
         $obj->mDepartments[i].department_id)}
      {assign var=selected value="class=\"selected\""}
    {/if}
    <li>
      {* Generate a link for a new department in the list *}
      <a {$selected} href="{$obj->mDepartments[i].link_to_department}">
        {$obj->mDepartments[i].name}
      </a>
    </li>
  {/section}
  </ul>
</div>
{* End departments list *}





	
	
{* categories_list.tpl *}
{load_presentation_object filename="categories_list" assign="obj"}
{* Start categories list *}
<div class="box">
  <p class="box-title">Choose a Category</p>
  <ul>
  {section name=i loop=$obj->mCategories}
    {assign var=selected value=""}
    {if ($obj->mSelectedCategory == $obj->mCategories[i].category_id)}
      {assign var=selected value="class=\"selected\""}
    {/if}
    <li>
      <a {$selected} href="{$obj->mCategories[i].link_to_category}">
        {$obj->mCategories[i].name}
      </a>
    </li>
  {/section}
  </ul>
</div>
{* End categories list *}

[PHPycho]

Once upon a time i used to use smarty, but since when MVC approach has been well adopted in PHP i just discarded it.
One question: Why to use another templating engine if PHP itself is a kind of templating engine?
May worth reading:
http://hasin.wordpress.com/2008/01/0...re-was-smarty/