How to convert string to XML object in JavaScript?

I am aware of this question already existing, but it has given me no luck.

I have an application which loads a physicial XML document via the following method:

jQuery.ajax({
    type: "GET",
    url: fileName,
    dataType: "xml",
    success: function (data) {
        // et开发者_开发问答c...
    }
});

I parse the XML and convert it into a string which is saved into a variable so that it can easily be stored in a database. How can I now convert the data in this variable back into an XML object so that it can be parsed as such?

Non-jQuery version:

var parseXml;

if (window.DOMParser) {
    parseXml = function(xmlStr) {
        return ( new window.DOMParser() ).parseFromString(xmlStr, "text/xml");
    };
} else if (typeof window.ActiveXObject != "undefined" && new window.ActiveXObject("Microsoft.XMLDOM")) {
    parseXml = function(xmlStr) {
        var xmlDoc = new window.ActiveXObject("Microsoft.XMLDOM");
        xmlDoc.async = "false";
        xmlDoc.loadXML(xmlStr);
        return xmlDoc;
    };
} else {
    parseXml = function() { return null; }
}

var xmlDoc = parseXml("<foo>Stuff</foo>");
if (xmlDoc) {
    window.alert(xmlDoc.documentElement.nodeName);
}

Since jQuery 1.5, you can use jQuery.parseXML(), which works in exactly the same way as the above code:

var xmlDoc = jQuery.parseXML("<foo>Stuff</foo>");
if (xmlDoc) {
    window.alert(xmlDoc.documentElement.nodeName);
}

With jquery, you can use $.parseXML(str), https://api.jquery.com/jQuery.parseXML/

If it's still in XML format you should be able to just wrap it in the jQuery function and start using jQuery to parse through it. For example:

$(xmlStringFromDB).find('foo');