Use the ref config option in ExtJS

var win = new Ext.Window({
    layout: 'fit',
    width: 300,
    height: 200,
    title: 'my window',
    items: [{
            ref: 'panel',
            xtype: 'panel', layout: 'form',
            frame: true, defaults: {xtype: 'textfield'},
            items: [
                {ref: '../nameField', fieldLabel: 'Name'},
                {ref: 'age', fieldLabel: 'Age'}
            ]
    }]
});

win.show();
//so now, with the above ref options, you can do:
win.nameField.setValue('name here');
win.panel.age.setValue(20);

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