How do I serialize a DOM to XML text, using JavaScript, in a cross browser way?

var xmlString = new XMLSerializer().serializeToString( doc );

function xml2Str(xmlNode) {
   try {
      // Gecko- and Webkit-based browsers (Firefox, Chrome), Opera.
      return (new XMLSerializer()).serializeToString(xmlNode);
  }
  catch (e) {
     try {
        // Internet Explorer.
        return xmlNode.xml;
     }
     catch (e) {
        //Other browsers without XML Serializer
        alert('Xmlserializer not supported');
     }
   }
   return false;
}