Ext.tree.TreePanel: How to add a filter?

Hi,

I have a tree in my application(ExtJs 3.4), how I can add a filter?

My code:

Code:

---

var treeLoader = new Ext.tree.TreeLoader({
            dataUrl: this.entrypoint,
            baseParams: {m:this.modName,a:'get-nodes'}
        });

        var clientiRootNode = new Ext.tree.AsyncTreeNode({id: 'clienti-root'});
       
        this.treePanel = new Ext.tree.TreePanel({
            loader: treeLoader,
            autoScroll: true,
            animate: true,
            autoScroll: true,
            border: false,
            title:'Clienti',
            // enableDD: true,
            root: clientiRootNode,
            selModel: new Ext.tree.DefaultSelectionModel(),
            lines: false,
            rootVisible: false,

            // tbar: tbar, //NOTA: se aggiungo la toolbar, quando nascondo il tree panel, il nodo root perde i nodi figlio
            listeners: {
                beforeexpand: function(p){p.getRootNode().expand();}
            }
        });

---

Ps: the tree is like a list, there are no nodes with deep more than "one"...

natively it doesn't support filtering