An alternative value key of the object passed to the options array
An alternative label key of the object passed to the options array
Localize value labels
Sort options alphabetically by label within groups
Customize the type of select that is created
An option to control the order and display of optgroup elements. The order of strings defines the displayed order of optgroup elements. A blank string may be used to define the position of ungrouped options. If not defined, the order of groups corresponds to the order of options.