How to format xml after add new object of xml?

The input xml :

    <books> 
        <book>
           <name>Name1</name?
           <title>Title</title>
        </book>
   </books>

I want to add new structure of book

        oContent = // the xml input

        var parseContentResult = jQuery.parseXML(oContent);
        var xmlContent = $(parseContentResult),
        booksAttr = xmlContent.find("books");
        //New XML
        var newXML =
            "\t\t\n<book>" +
            "\n\t\t\t<name>" + nameID + "</name>" + 
            "\n\t\t\t<title>" + titleId + "</title>"; 
        }
        newXML +=   "\t\t</book>\n" ;
        //Update XML
        var parseResult = jQuery.parseXML(newXML );
        var xmlResult = $(parseResult );
        booksAttr.append(xmlResult .find("book"));

        return (new XMLSerializer()).serializeToString(xmlContent[0]);

The problem that I don't get the result in good strcture Did I do something wrong ?