在actionscript中,检查xml节点属性是否存在的最佳方法是什么？

var xml:XML = <root>
    <item id="1">Item 1</item>
    <item id="2">Item 2</item>
    <item>Item 3</item>
</root>;

for each (var item:XML in xml.item) {
    if (item.hasOwnProperty("@id")) {
        trace("Item has an id attribute: " + item.@id);
    } else {
        trace("Item does not have an id attribute.");
    }
}