Why can´t update my tree?

I write a little code on a file js:

function load_tree()
{ var tree = new dhtmlXTreeObject(‘treeboxbox_tree’, ‘100%’, ‘100%’, 0);
tree.setSkin(‘dhx_skyblue’);
tree.setImagePath(“includes/codebase/imgs/csh_bluebooks/”);
tree.enableDragAndDrop(true);
tree.enableThreeStateCheckboxes(true);
tree.loadXML(‘xml/tree/1996.xml’);
}

and I call the function on a page html:

The problem is when I use a combo and doesn’t works.

File 2002 File 1994 File 1995 File 1996

Can you help me solve this?

Thanks.

function load_tree(){ var tree =

“tree” should be a public variable if you want to use in code outside load_tree() function.

function load_tree(){
tree = new dhtmlXTreeObject(‘treeboxbox_tree’, ‘100%’, ‘100%’, 0);