Use DOM to operate XML

When using AJAX, although the JSON data format is simple and easy to use, the server-side language does not support JSON as well as XML. Sometimes we need to return the XML data format from the background to the foreground, therefore, it is necessary to learn how javascript uses DOM to operate XML. The following section describes how javascript uses DOM to operate X... syntaxHighlighter. when using AJAX, although the JSON data format is simple and easy to use, the server-side language does not support JSON as well as XML. Sometimes we need to return the XML data format from the background to the foreground, therefore, it is necessary to learn how to use javascript to operate XML using DOM. The following code uses javascript to operate XML 1. Loading XML documents [javascript] function loadXMLDocument (flag, xmlDoc) {// flag = true indicates the XML document, otherwise it is an XML string // if (window. activeXObject) {var CtiveName = ['msxml2. DOMDocument ', 'Microsoft. xmlDom ']; var xmlObj; for (var I = 0; I try {xmlObj = new ActiveXObject (activeName [I]); break;} catch (e) {}}// object created successfully if (xmlObj) {// load XML document xmlObj in synchronous mode. async = false; // load the xml document if (flag) {xmlObj. load (xmlDoc);} else {// load the xml string xmlObj. loadXML (xmlDoc);} // return the Root Node object // return xmlObj; // return the root element object return xmlObj.doc umentElement ;} else {// object creation failed alert ("xmlbeannet object creation failed"); re Turn null;} // FireFox Loading Method} else if (document. implementation. createDocument) {var xmlObj; if (flag) {// load xml document xmlObj = document. implementation. createDocument ("", "", null); if (xmlObj) {xmlObj. async = false; xmlObj. load (xmlDoc); return xmlObj // return xmlObj.doc umentElement;} else {alert ("failed to create object"); return null ;}} else {// load the xml string xmlObj = new DOMParser (); var docRoot = xmlObj. parseFromString (xmlDoc, 'text/x Ml '); return docRoot.doc umentElement;} else {alert ("xmlbeannet object creation failed"); return null ;}2. After the XML file is loaded, the rest is how to use the XPATH technology to get the content in XML. Here we usually use two methods: selectNodes () and selectSingleNode () 2.1 selectSingleNode () method [javascript] function selectSingleNode (xmlDom, sXpath) {if (window. activeXObject) {// IE browser return xmlDom. selectSingleNode (sXpath);} else if (window. XPathEvaluator) {// firefox browser var xpathObj = new xpatev Aluator (); if (xpathObj) {var result = xpathObj. evaluate (sXpath, xmlDom, null, XPathResult. FIRST_ORDERED_NODE_TYPE, null); return result. singleNodeValue ;}else {return null ;}} else {return null ;}} 2.2 selectNodes () method [javascript] function selectNodes (xmlDom, sXpath) {if (window. activeXObject) {// IE browser return xmlDom. selectNodes (sXpath);} else if (window. XPathEvaluator) {// firefox browser var xpathObj = new xpatev Aluator (); if (xpathObj) {var result = xpathObj. evaluate (sXpath, xmlDom, null, XPathResult. ORDERED_NODE_ITERATOR_TYPE, null); var nodes = new Array (); var node; while (node = result. iterateNext ())! = Null) {nodes. push (node) ;}return nodes ;}else {return null ;}} else {return null ;}}