Use the following code to create a basic inputEx TreeField.
new Y.inputEx.TreeField({ parentEl: 'container1', elementType: { type: 'inplaceedit', visu: { visuType: "func", func: function (val) { var url = "http://" + val + "/favicon.ico"; return '' + val; } }, editorField: { type: 'string' } }, value: 'facebook.com' });