javascript跨浏览器操作xml

//跨浏览器获取xmlDom

function getXMLDOM(xmlStr) {
    var xmlDom = null;
    if (typeof window.DOMParser != 'undefined') {
        xmlDom = (new DOMParser).parseFromString(xmlStr,'text/xml'); //创建xmlDom对象
        var errors = xmlDom.getElementsByTagName('parsererror');
        if(errors.length > 0) {
            throw new Error('XML格式有误:'+errors[0].textContent);
        }
        return xmlDom;
    } else if (typeof window.ActiveXObject != 'undefined') {
        var version = [
            'MSXML2.DOMDocument.6.0',
            'MSXML2.DOMDocument.3.0',
            'MSXML2.DOMDocument'
        ];
        for(var i=0;i<version.length;i++) {
            try {
                var xmlDom = new ActiveXObject(version[i]);
            } catch (e) {
                //遇到错误跳过,继续执行try
            }
        }
        xmlDom.loadXML(xmlStr);
        if(xmlDom.parseError != 0) { //使用 !+ 号
            throw new Error('错误信息为:' + xmlDom.parseError.reason);
        }
        return xmlDom;
    } else {
        throw new Error('系统或浏览器不支持xmlDom对象!');
    }
    return xmlDom;
}

/*
DOM2没有序列化XML的属性，XMLSerializer类型来帮助序列化XML字符串。
IE9、Safari、Chrome和Opera都支持这个类型。
*/

function serializerXML(xmlDom) {
    var xml = null;
    if(typeof window.XMLSerializer != 'undefined') {//w3c的序列化
            var serializer = new XMLSerializer();
            xml = serializer.serializeToString(xmlDom);
    } else if(typeof xmlDom.xml != 'undefined') { //ie直接序列化
            xml = xmlDom.xml;
    }
    return xml;
}

//跨浏览器获取xml单一节点

function selectSingleNode(xmlDom,xpath) {
    var node = null;
    if(typeof xmlDom.evaluate != 'undefined') { //w3c
        var patt = /[(d+)]/;
        var num = null;
        var flag = xpath.match(patt);
        if (flag) {
            num = parseInt(RegExp.$1) + 1;//w3c下标从1开始,如0加1
            xpath = xpath.replace(patt,'['+num+']'); //root/user[1]
        }
        var result = xmlDom.evaluate(xpath,xmlDom,null,XPathResult.FIRST_ORDERED_NODE_TYPE,null);
        if(result != null) {
            node = result.singleNodeValue; //w3c默认的下标是1
        }
    } else if (typeof xmlDom.selectSingleNode != 'undefined') {//ie中unknown而非 undefined
        node = xmlDom.selectSingleNode(xpath);
    }
    return node;
}

//跨浏览器获取xml所有节点

function selectNodes(xmlDom,xpath) {
    var nodes = [];
    if(typeof xmlDom.evaluate != 'undefined') { //w3c
        var patt = /[(d+)]/;
        var num = null;
        var flag = xpath.match(patt);
        if(flag) {
            num = parseInt(RegExp.$1) + 1;
            xpath = xpath.replace(patt,'['+num+']');
        }
        var result = xmlDom.evaluate(xpath,xmlDom,null,XPathResult.ORDERED_NODE_ITERATOR_TYPE,null);
        var node = null;
        if(result != null) {
            while ((node = result.iterateNext()) !== null) {
                nodes.push(node);
            }
        }
    } else if (typeof xmlDom.selectNodes != 'undefined') { //unkonwn
        nodes = xmlDom.selectNodes(xpath);
    }
    return nodes;
}

var xmlStr = '<root><name id="d1">du1</name><name id="d2">du2</name></root>';
var xmlDom = getXMLDOM(xmlStr);
var nodes = selectNodes(xmlDom,'root/name');
//alert(nodes.length);
//alert(serializerXML(xmlDom)); //序列化xmlStr
//alert(serializerXML(selectSingleNode(xmlDom,'root/name[0]'))); //序列化单一节点

alert(serializerXML(nodes[0]));//<name id="d1">du1</name>
alert(serializerXML(nodes[1]));