Question

Using Jquery I am parsing an XML file and adding an attribute to every element nodes.
After manipulated xml is returned to the caller I can’t get the added attibute, it says it is undefined.

function loadTreeML(dname){

    var xmlDoc;
        $.ajaxSetup({
          async: false
        });
        $.ajax({
            type: "GET",
            url: dname,
            dataType: "xml",

            success: function(xml) {

             var firstBranch =$(xml).find('branch').get(0);

             if (typeof firstBranch != "undefined")
                traverse(firstBranch, {"children":1, "siblings":0, "level":-1, "depth":0, "weight":1, "leaves":0, "strahlernum":0});
             xmlDoc = xml;


            }

        });

//should return manipulated xml  
            return  xmlDoc;
        }

//updating attribute in traverse function
    $(tree).attr('stats',child_stats);

Attribute I am adding is JSON data in format

{"children":1, "siblings":0, "level":-1, "depth":0, "weight":1, "leaves":0, "strahlernum":0}



function traverse(tree, parent_stats) 
{
    var child_stats = {"children":0, "siblings":0, "level":0, "depth":0, "weight":1, "leaves":0, "strahlernum":0};  
    //Counting the child node

    $(tree).children().each(function(){

            var kid = $(this);
            if((kid.get(0).tagName.toLowerCase()== "branch")|| (kid.get(0).tagName.toLowerCase() == "leaf"))
            child_stats.children++;

        });

     //alert(child_stats.children); 
    //Sibling
     child_stats.siblings = parent_stats.children - 1;
     //alert(child_stats.siblings );
    //Level
     child_stats.level = parent_stats.level + 1;

     //DFS
    if($(tree).get(0).tagName.toLowerCase() == "branch")
    {
        var offset = -1;
        $(tree).children().each(function(){

            var kid = $(this);
            if((kid.get(0).tagName.toLowerCase()== "branch")|| (kid.get(0).tagName.toLowerCase() == "leaf")){
            var temp_stats = traverse(kid,child_stats);
                //count leaves
                child_stats.leaves += temp_stats.leaves;
                //determine depth
                if(child_stats.depth < temp_stats.depth+1) child_stats.depth = temp_stats.depth+1;
                //compute weight
                child_stats.weight += temp_stats.weight;
                //computer strahler
                if ((child_stats.strahlernum != temp_stats.strahlernum)&&(child_stats.strahlernum != 0)) offset = -2;
                child_stats.strahlernum = Math.max(child_stats.strahlernum, temp_stats.strahlernum);

            }
            child_stats.strahlernum += child_stats.children + offset;

        });

    } 
    else { //leaf
       child_stats.leaves = child_stats.strahlernum = 1;
    }

    //Adding stats attribute write to XML
    $(tree).attr('stats',child_stats);

    return child_stats;
}

I am not getting the stats attribute in the returned xmlDoc that i have added. It is saying undefined. Let me know what I am doing wrong here.
Thank you very much for your time.

Answer 1

Fixed the stats property problem.
Accoring to JQuery
.attr() should not be used on plain objects, arrays, the window,

You have to use .data(‘stats’, {}) to set object base data like json. I have added the code in stats property is showing properly now

$(tree).data('stats',child_stats);