Disable asp.net radiobutton with javascript

private static void DisableControl(WebControl control)
    {

        if (control is CheckBox)
        {
            ((CheckBox)control).InputAttributes.Add("disabled", "disabled");

        }
        else if (control is RadioButton)
        {

        }
        else if (control is ImageButton)
        {
            ((ImageButton)control).Enabled = false;
        }
        else
        {
            control.Attributes.Add("readonly", "readonly");
        }
    }

private static void DisableControl(WebControl control)
    {
        Type controlType = control.GetType();

        if (controlType == typeof(CheckBox))
        {
            ((CheckBox)control).InputAttributes.Add("disabled", "disabled");

        }
        else if (controlType == typeof(RadioButton))
        {
            ((RadioButton)control).InputAttributes.Add("disabled", "true");
        }
        else if (controlType == typeof(ImageButton))
        {
            ((ImageButton)control).Enabled = false;
        }
        else
        {
            control.Attributes.Add("readonly", "readonly");
        }
    }