How to Add custom Attribute in XML

Question

How to add Custom attribute recusrivly. With sequence order.
//Before xml:-
var myxml:XML=
<root>
<leval0 >
<leval1 >
<leval2></leval2>
<leval2></leval2>
</leval1>
<leval1 >
<leval2></leval2>
<leval2></leval2>
</leval1>
</leval0>
</root>
////After xml:
var myxml:XML=
<root>
<leval0 levalid="0" >
<leval1 levalid="0_0" >
<leval2 levalid="0_0_0"></leval2>
<leval2 levalid="0_0_1"></leval2>
</leval1>
<leval1 levalid="0_1" >
<leval2 levalid="0_1_0"></leval2>
<leval2 levalid="0_1_1"></leval2>
</leval1>
</leval0>
</root>

Answer 1

//call this method
            trace(addAttribute(myxml));
//method
            private function addAttribute(node:XML, depth:String = ""):XML
                if (node.hasComplexContent())
                    var count:int = 0;
                    var prefix:String = 0 < depth.length ? depth + "_" : "";
                    var currentAtt:String;
                    for each (var nodeItem:XML in node.children())
                        currentAtt = prefix + count;
                        nodeItem.@levalid = currentAtt;
                        addAttribute(nodeItem,currentAtt);
                        count++;
                return node;