To create a node, following item show a static text of "Node 1".

  $node1 = $navtree->CreateNode($main_node, $t_folder, "open" ,"Node 1", "text data");

I can easily create a hyper-link:

    $action="<A HREF='mypage.html'>";
    $node1 = $navtree->CreateNode($main_node, $t_folder, "open" ,$action, "text data");

Note that due to the interaction with the Javascript, care has to be taken in the quote. I tried out the following combination and it owrks:
     $action="<A HREF=\"javascript:function1(124, 'asfdasfasf')\";">;
That is, use ' for one level quote. For two level quote, use \" as the outer quote and ' as inner quote.

In a frame page environment,
    $action="<A HREF='mypage.html' target='right'>";

To start a javascript,
    $action="<A HREF='javascript:jsfunction();'>";

To start a thread environment,
    $action='<A HREF='javascript:PostReply($node1);'>";
The value $node1 is the value of the existing node, it will be used as the parent of the new node in the PostReply routine.

My SQL Table looks something like this:
    id: int, autoincrement, primary index
    parent: int, points to parent node id
    action: text string to be displayed

If I am free, I will post sample script on how to integrate mysql with this NAVTREE class.

Rgds,
Mark