下面的代碼定義了一個完整的ext treepanel的實例，其中，對checkchange事件的處理，使單擊父親節點時對下面的子節點全部選中或取消選中。
sysFunClassTree = new Ext.tree.TreePanel({
id:'sysFunClassTree',split:true,collapsible:true,rootVisible:false,name:'sysFunClassTree',autoScroll:true,border:true,
region:'east',title:'功能分類樹',width:200,
loader:new Ext.tree.TreeLoader({dataUrl:'http://localhost:8080/jeasyweb/treeSysFunClass.do',baseParams:{'_tree_checkbox':'true'}})
});
sysFunClassTree_root = new Ext.tree.AsyncTreeNode({
text:'Ext TreeRoot',id:'src_root'
});
sysFunClassTree.setRootNode(sysFunClassTree_root);
sysFunClassTree.on('click', function(node, e){treeClick(node, e);});
sysFunClassTree.on('checkchange', function(node, flag) {
if (node.hasChildNodes()) {
node.eachChild(function(child) {
child.ui.toggleCheck(flag);
child.attributes.checked = flag;
child.fireEvent('checkchange', child, flag);
});
}
});