Question

The following snippet of code converts a Javascript object into an XML string using the createDocument and XMLSerializer APIs. The problem is that it generates different outputs on Chrome (23.0.1271.101) and Firefox (14.0.1) browsers.

var item = { _dto: {...} }; // the 'model' object
var xmlDto = $('<Column />'); // this is eventually serialized and sent to the server
var optionalTags = ['Abstract', 'Note', 'Size', 'Digits', 'Nullable', 'AutoUpdate', 'DataType'];

// convert badgerfish JSON back to XML.
// use XML because it is not possible serialize JSON and preserve key order.
var xmlDoc = document.implementation.createDocument("http://example.org/v1", "Column", null);
var root = xmlDoc.childNodes[0];
var nameTag = xmlDoc.createElement("Name");
nameTag.setAttribute('uuid', item._dto['Name']['@uuid']);
nameTag.textContent=item._dto['Name']['$'];
root.appendChild(nameTag);
optionalTags.map(function (tagName) {
    var tag = xmlDoc.createElement(tagName);
    tag.textContent=item._dto[tagName];
    if (item._dto.hasOwnProperty(tagName)) {
        tag.textContent=item._dto[tagName];
        root.appendChild(tag);
    }
});

var xmlStr = new XMLSerializer().serializeToString(xmlDoc);
xmlStr = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'+xmlStr;

On Chrome, the following desired/expected output is generated:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <Column xmlns="http://example.org/v1">
          <Name uuid="001b5cbe-bab7-4880-90b6-9e8f47f6e4af">FAILED_ID</Name>
          <Size>38</Size>
          <Digits>0</Digits>
          <Nullable>true</Nullable>
          <AutoUpdate>false</AutoUpdate>
          <DataType>NUMERIC</DataType>
    </Column>

But in Firefox, the generated output has the xmlns attribute inserted in every tag with an empty value:

     <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
     <Column xmlns="http://example.org/v1">
          <Name xmlns="" uuid="001b5cbe-bab7-4880-90b6-9e8f47f6e4af">FAILED_ID</Name>
          <Size xmlns="">38</Size>
          <Digits xmlns="">0</Digits>
          <Nullable xmlns="">true</Nullable>
          <AutoUpdate xmlns="">false</AutoUpdate>
          <DataType xmlns="">NUMERIC</DataType>
     </Column>

It looks like the XMLSerializer in Firefox and Chrome have subtle differences but I need to verify this. In any case, the Firefox output is invalid XML. Can somebody shed some light on this?

Is there a better way to generate an XML document in the browser?

I wouldn’t be doing this if in the first place I had a way to serialize to JSON with the ability to preserve key order.

Answer 1

The Firefox serialization is correct. When you create those elements with createElement, not createElementNS, that puts them in the null namespace (you can check by examining the namespaceURI of the elements after you create them). However parsing the serialization Chrome produces would put them in the http://example.org/v1 namespace.

And yes, the Firefox output is valid XML. What made you think it’s not valid?

I filed https://bugs.webkit.org/show_bug.cgi?id=106531