I have a variable string that contains well-formed and valid XML. I need to use JavaScript code to parse this feed.
How can I accomplish this using (browser-compatible) JavaScript code?
This question is related to
javascript
xml
parsing
Disclaimer : I've created fast-xml-parser
I have created fast-xml-parser to parse a XML string into JS/JSON object or intermediate traversal object. It is expected to be compatible in all the browsers (however tested on Chrome, Firefox, and IE only).
Usage
var options = { //default
attrPrefix : "@_",
attrNodeName: false,
textNodeName : "#text",
ignoreNonTextNodeAttr : true,
ignoreTextNodeAttr : true,
ignoreNameSpace : true,
ignoreRootElement : false,
textNodeConversion : true,
textAttrConversion : false,
arrayMode : false
};
if(parser.validate(xmlData)){//optional
var jsonObj = parser.parse(xmlData, options);
}
//Intermediate obj
var tObj = parser.getTraversalObj(xmlData,options);
:
var jsonObj = parser.convertToJson(tObj);
Note: It doesn't use DOM parser but parse the string using RE and convert it into JS/JSON object.
Marknote is a nice lightweight cross-browser JavaScript XML parser. It's object-oriented and it's got plenty of examples, plus the API is documented. It's fairly new, but it has worked nicely in one of my projects so far. One thing I like about it is that it will read XML directly from strings or URLs and you can also use it to convert the XML into JSON.
Here's an example of what you can do with Marknote:
var str = '<books>' +
' <book title="A Tale of Two Cities"/>' +
' <book title="1984"/>' +
'</books>';
var parser = new marknote.Parser();
var doc = parser.parse(str);
var bookEls = doc.getRootElement().getChildElements();
for (var i=0; i<bookEls.length; i++) {
var bookEl = bookEls[i];
// alerts "Element name is 'book' and book title is '...'"
alert("Element name is '" + bookEl.getName() +
"' and book title is '" +
bookEl.getAttributeValue("title") + "'"
);
}
Updated answer for 2017
The following will parse an XML string into an XML document in all major browsers. Unless you need support for IE <= 8 or some obscure browser, you could use the following function:
function parseXml(xmlStr) {
return new window.DOMParser().parseFromString(xmlStr, "text/xml");
}
If you need to support IE <= 8, the following will do the job:
var parseXml;
if (typeof window.DOMParser != "undefined") {
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 {
throw new Error("No XML parser found");
}
Once you have a Document obtained via parseXml, you can use the usual DOM traversal methods/properties such as childNodes and getElementsByTagName() to get the nodes you want.
Example usage:
var xml = parseXml("<foo>Stuff</foo>");
alert(xml.documentElement.nodeName);
If you're using jQuery, from version 1.5 you can use its built-in parseXML() method, which is functionally identical to the function above.
var xml = $.parseXML("<foo>Stuff</foo>");
alert(xml.documentElement.nodeName);
<script language="JavaScript">
function importXML()
{
if (document.implementation && document.implementation.createDocument)
{
xmlDoc = document.implementation.createDocument("", "", null);
xmlDoc.onload = createTable;
}
else if (window.ActiveXObject)
{
xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
xmlDoc.onreadystatechange = function () {
if (xmlDoc.readyState == 4) createTable()
};
}
else
{
alert('Your browser can\'t handle this script');
return;
}
xmlDoc.load("emperors.xml");
}
function createTable()
{
var theData="";
var x = xmlDoc.getElementsByTagName('emperor');
var newEl = document.createElement('TABLE');
newEl.setAttribute('cellPadding',3);
newEl.setAttribute('cellSpacing',0);
newEl.setAttribute('border',1);
var tmp = document.createElement('TBODY');
newEl.appendChild(tmp);
var row = document.createElement('TR');
for (j=0;j<x[0].childNodes.length;j++)
{
if (x[0].childNodes[j].nodeType != 1) continue;
var container = document.createElement('TH');
theData = document.createTextNode(x[0].childNodes[j].nodeName);
container.appendChild(theData);
row.appendChild(container);
}
tmp.appendChild(row);
for (i=0;i<x.length;i++)
{
var row = document.createElement('TR');
for (j=0;j<x[i].childNodes.length;j++)
{
if (x[i].childNodes[j].nodeType != 1) continue;
var container = document.createElement('TD');
var theData = document.createTextNode(x[i].childNodes[j].firstChild.nodeValue);
container.appendChild(theData);
row.appendChild(container);
}
tmp.appendChild(row);
}
document.getElementById('writeroot').appendChild(newEl);
}
</script>
</HEAD>
<BODY onLoad="javascript:importXML();">
<p id=writeroot> </p>
</BODY>
For more info refer this http://www.easycodingclub.com/xml-parser-in-javascript/javascript-tutorials/
You can also through the jquery function($.parseXML) to manipulate xml string
example javascript:
var xmlString = '<languages><language name="c"></language><language name="php"></language></languages>';
var xmlDoc = $.parseXML(xmlString);
$(xmlDoc).find('name').each(function(){
console.log('name:'+$(this).attr('name'))
})
Most examples on the web (and some presented above) show how to load an XML from a file in a browser compatible manner. This proves easy, except in the case of Google Chrome which does not support the document.implementation.createDocument() method. When using Chrome, in order to load an XML file into a XmlDocument object, you need to use the inbuilt XmlHttp object and then load the file by passing it's URI.
In your case, the scenario is different, because you want to load the XML from a string variable, not a URL. For this requirement however, Chrome supposedly works just like Mozilla (or so I've heard) and supports the parseFromString() method.
Here is a function I use (it's part of the Browser compatibility library I'm currently building):
function LoadXMLString(xmlString)
{
// ObjectExists checks if the passed parameter is not null.
// isString (as the name suggests) checks if the type is a valid string.
if (ObjectExists(xmlString) && isString(xmlString))
{
var xDoc;
// The GetBrowserType function returns a 2-letter code representing
// ...the type of browser.
var bType = GetBrowserType();
switch(bType)
{
case "ie":
// This actually calls into a function that returns a DOMDocument
// on the basis of the MSXML version installed.
// Simplified here for illustration.
xDoc = new ActiveXObject("MSXML2.DOMDocument")
xDoc.async = false;
xDoc.loadXML(xmlString);
break;
default:
var dp = new DOMParser();
xDoc = dp.parseFromString(xmlString, "text/xml");
break;
}
return xDoc;
}
else
return null;
}
Apparently jQuery now provides jQuery.parseXML http://api.jquery.com/jQuery.parseXML/ as of version 1.5
jQuery.parseXML( data )
Returns: XMLDocument
I've always used the approach below which works in IE and Firefox.
Example XML:
<fruits>
<fruit name="Apple" colour="Green" />
<fruit name="Banana" colour="Yellow" />
</fruits>
JavaScript:
function getFruits(xml) {
var fruits = xml.getElementsByTagName("fruits")[0];
if (fruits) {
var fruitsNodes = fruits.childNodes;
if (fruitsNodes) {
for (var i = 0; i < fruitsNodes.length; i++) {
var name = fruitsNodes[i].getAttribute("name");
var colour = fruitsNodes[i].getAttribute("colour");
alert("Fruit " + name + " is coloured " + colour);
}
}
}
}
Please take a look at XML DOM Parser (W3Schools). It's a tutorial on XML DOM parsing. The actual DOM parser differs from browser to browser but the DOM API is standardised and remains the same (more or less).
Alternatively use E4X if you can restrict yourself to Firefox. It's relatively easier to use and it's part of JavaScript since version 1.6. Here is a small sample usage...
//Using E4X
var xmlDoc=new XML();
xmlDoc.load("note.xml");
document.write(xmlDoc.body); //Note: 'body' is actually a tag in note.xml,
//but it can be accessed as if it were a regular property of xmlDoc.
Source: Stackoverflow.com