Basic question, duplicating a circle with javascript

Question

Hello. I'm trying to build something like a bullseye using javascript. I'm new to scripting for Illustrator but I've used javascript before so I thought it would be simple, but maybe I'm missing some basic notions here.
I'm using Illustrator CS6. I created a blank document and drew a circle with a 1pt black stroke and no fill. Selecting that circle, I my script to copy and paste it in front and increase its radius by one centimeter. I attempted a simple duplication first:
if ( app.documents.length > 0 ) {
    var numberOfItems = 3;
    var selectedItem = app.activeDocument.selection;
    for (i=0; i < numberOfItems; i++) {
         newItem = selectedItem.duplicate();
With my circle selected I get an error message saying "Error 24: selectedItem.duplicate() is not a function". What am I doing wrong?
Thank you in advance.

Answer 1

if ( app.documents.length > 0 ) {
    var numberOfItems = 3;
    var selectedItem = app.activeDocument.selection;
    for (i=0; i < numberOfItems; i++) {
        newItem = selectedItem[i].duplicate();
maguskrool wrote:
Thanks. I got an error using this option, though, not sure why but it says the last item (in this case, selectedItem[i] when i = 2) is undefined.
Your script says:
When (min) one document is open --> say numberOfItems = 3        //the counter is 3 --> min three or more items should be selected by yourself
selectedItem --> is the array of all selected items in document
then go for counter = 0 to counter < numberOfItems (means 3-1) -->
counter 0 = loop 1 --> duplicate this (item 1 of 3 selected) item
counter 1 = loop 2 --> duplicate this (item 2 of 3 selected) item   //when only 1 item is selected by yourself --> result is undefined
counter 2 = loop 3 --> duplicate this (item 3 of 3 selected) item   //when only 2 items are selected by yourself --> result is undefined
It's equal, how many items are selected by user - but min you have defined here --> var numberOfItems = 3; 
You need in this example a selection of three items (better: three selected items)