Class: HTML_QuickForm_ComboBox

With $options you can specify the CSS class to use with different aspects of the combobox. The compobox's aspects that you can change assigning different CSS class are:

    Aspect            Description                                    Default class
  boxClass        external box                                comboBox
     inputClass        input textfield                                comboBoxInput
    buttonClass        dropdown button (if used)                    comboBoxButton
    arrowClass        dropdown arrow (if used)                    comboBoxArrow
    containerClass    dropdown container                            comboBoxContainer
    optionClass        single option inside dropdown container        comboBoxOption
    optionClassOver    single option when mouse is over            comboBoxOptionOver

You can change the button (value)label with buttonValue option, es.: butonValue => 'V' or specify images to use to render the button:

    arrowImage            image used to render the button in normal state
    arrowImageOver        image used when the mouse is over the button
    arrowImageDown        image used when the button in clicked