Option() - Web APIs
syntax var optionelementreference = new option(text, value, defaultselected, selected); parameters text optional a domstring representing the content of the element, i.e.
... defaultselected optional a boolean that sets the selected attribute value, i.e.
...if omitted, even if the defaultselected argument is true, the option is not selected.

HTMLOptionElement - Web APIs
htmloptionelement.defaultselected is a boolean that contains the initial value of the selected html attribute, indicating whether the option is selected by default or not.
...it has four values: the text to display, text, the value associated, value, the value of defaultselected, and the value of selected.
... the defaultselected property is no longer read-only.