What is the difference between calling objects of Select, Listbox, Radiobutton array, and checkboxes array in javascript

If you have Select, it will be accessed in javascript like this:
var country = document.getElementById(“ddlcountry”);
if( country.selectedIndex == 0)
alert(“Country must be selected”);
return false;

To retrieve values and text of select, we use options

var selected = country.selectedIndex;
document.write(country.options[selected].value + ” ” +

if you have radiobutton array
var radsuit = document.getElementsByName(“radSuit”);
you will call elements like this

if you have checkboxes array
var chkSuit = document.getElementsByName(“chkSuit”);

you will call elements like this:

if(chkSuit[i].checked == true)

if you have multiple select
var ddm = document.getElementById(“ddlmulti”);