sets focus to a Form control by its id
name|id: string - the name of the control or its id (if the name attribute is not defined in the config of the control)
The method is applicable to Button, DatePicker, Checkbox, CheckboxGroup, ColorPicker, Combo, Input, RadioGroup, Select, Slider, Textarea, TimePicker controls of Form.
Related sample: Form. Set Focus On Control
added in v7.0