ExtJS how to get checked nodes on submit?

Question

I use ExtJS 1.0.1 (in magento)

I would like to get all checked nodes on form submit. And I stucked here:

tree.html (initialization):

tree<?php echo $this->getId() ?> = new Ext.tree.TreePanel.Enhanced('<?php echo $_divId ?>', {
            animate:          false,
            loader:           categoryLoader,
            enableDD:         false,
            containerScroll:  true,
            rootVisible:      '<?php echo $this->getRoot()->getIsVisible() ?>',
            useAjax:          true,
            currentNodeId:    <?php echo (int) $this->getCategoryId() ?>,
            addNodeTo:        false
        });

On submit function:

function submit()
{

   console.log(tree'.$this->getId().');
   // got html code <div id="treeoptions_fieldset992cb0dd9a7da511e5596a229a5386d5_select_catalogb0f2cd4faa4f13b72f0df314bdc222ec" class="tree x-tree"><ul class="x-tree-root-ct x-tree-lines" id="ext-gen5859">...</ul></div>

   var checked_nodes = tree'.$this->getId().'.getChecked();
   // got an error Uncaught TypeError: Object #<HTMLDivElement> has no method 'getChecked'
}

Magento uses prototypeJS in admin panel. The question is how to address to checked_nodes to run getChecked()?

Answer 1

get works!

I created the object after treegetId() ?> init:

function av_OkButton()
    {
        var tree = null;

        this.onPress = function()
        {
            var ids = this.tree.getChecked();
        }

        this.getTree = function()
        {
            return this.tree;
        }

        this.setTree = function(treeObj)
        {
            this.tree = treeObj;

            return this;
        }
    }

okButton = new av_OkButton;
okButton.setTree(tree<?php echo $this->getId() ?>);

And then created submit button:

Cannot understand what the difference between I did and what I have now but it works for me