JS noob needs help (simple)

I am making a function that changes all options to their default values (radios, checkboxes, dropdown and text boxes). Right now I only know how to fill a textbox via JS...

var efour = document.getElementById("four");
efour.value = "Text....";

four is the textbox


How do I change the rest of the options? Radios, checkboxes and dropdowns.

 

selected, option/value, checked, for divs/spans it's innerHTML


(no particular order)