$.fn.replaceWithXML = function replaceWithXML(ele) {
        var xml = this.html();
        return $('<dummy />').append($(ele).append(xml)).html();
    }

xml = '<field><col>Col1</col></field>'
 xml = $.parseXML(xml);

var xml_node = '<column></column>';
$(root).append(xml_node,{html: $(xml ).find('field').html()});

$(root).append($(xml_node).append($(xml ).find('field').html()));

xml = '<field><col>Col1</col></filed>'

xml = '<field><col>Col1</col></field>'

var xml = '<field><col>Col1</col></field>';
xml = $.parseXML(xml);
console.log(xml);
alert($(xml).find("col").html());