Id Of Div Elements For Draggable?

I am trying to create some ajax/javascript to append the scriptaculous Draggable to a number of div elements with a className of draggable. The problem is i need to get the id's of each element to make them draggable, as simply making all div elements on the page draggable would effect other elements on the page which I dont want to be so.I need to:-

1.create a collection of div elements with className - draggable

2. make a list of all the element id's

3. make all elements with said id's draggable

I have left out the draggable part from the code, I have simply been trying to get the element id's to display so far

var dv;
var dh;

dv = document.getElementsByTagName('div');
if (dv.className == 'draggable')[code].....

I keep getting the alert message "no id" loaded