Array.sortOn() question...how is this working?

programming flash
1

So I have the following code to sort an XML list and then sort it on the “StartDate” property. The code below works fine. I’m actually wondering why its working because when I lookup the reference for Array.sortOn() this shouldn’t be working. I have no key defined in my array yet its still sorting okay…can anyone explain why its working or what its actually doing??

[AS]function sortEventXML() {

var eventList = events_xml.firstChild.childNodes;


for (var i=0; i <= eventList.length; i++) {
    
    //    Populate the Event Array
    //    0 - Event
    //    1 - StartDate
    //    2 - EndDate
    //    3 - Speaker
    //    4 - Audience
    //    5 - Sponsor
    //    6 - Description
    
    eventInfo_array* = [eventList*.attributes.Event, 
                            eventList*.attributes.StartDate, 
                            eventList*.attributes.EndDate, 
                            eventList*.attributes.Speaker, 
                            eventList*.attributes.Audience, 
                            eventList*.attributes.Sponsor, 
                            eventList*.attributes.Description];
}    

trace("Before Sort: ")
for (i=0; i < eventInfo_array.length-1; i++) {
    trace(eventInfo_array*[1])
}

//    Sort array by the StartDate
eventInfo_array.sortOn(1);  //  How does this line work??

trace("After Sort: ")
for (i=0; i < eventInfo_array.length; i++) {
    trace(eventInfo_array*[1])
}

}
[/AS]