New to Jscript

Hi,
I'm new to Jscript and need help. I'm trying to get a list of all selected items from a CRM view to pass to a workflow

So far I have

function run(selectedItems)
{
var selectedItem = selectedItems[0];
alert("Id=" + selectedItem.Id );
}

which will throw a dialog box up with the id of the first selected record.
What I need to get to is

if only 1 record is selected ( scuse the code as Its all I know )

dim output as string = selecteditem.id

if multiple records are selected theni need

dim output as string and the string to look like selecteditem1.id;selecteditem2.id; etc

is this possible in Jasript?