Parsing XML with Javascript

rvanandel · August 28th, 2005, 09:19 PM

I am working on a web application using the xmlhttprequest object. The returned xml looks something like this

<event>
   <name>Event Name</name>
   <start>August 10, 2005</start>
   <end>August 11, 2005</end>
   <participant>
      <firstname>John</firstname>
      <lastname>Doe</lastname>
   </participant>
   <participant>
      <firstname>Jane</firstname>
      <lastname>Doe</lastname>
   </participant>
</event>

I wrote a function that parses the returned XML but can't figure out how to return the elements in between the participant tags. Here's what I have so far

function parseXML(theXML) {
   var participants = theXML.getElementsByTagName("participant");
}

When I do a count of childnodes for each participants object, I would expect to see 2 childnodes, but instead I get much more.

For example, using the code snippet alert(participants[0].childNodes.length), I would expect to see 2 (firstname and lastname). Is there another way to do this, or is there any websites that you can direct me to that will give me some in depth information on parsing XML documents.

Thanks
Robbert van Andel

joefawcett · August 29th, 2005, 03:39 AM

On of your problems arises from the fact that nodes includes text nodes as well as elements.

Although learning XPath is a big step it makes extracting information so much easier and for simple documents it resembles a file path.
The path to the <participant>s would be:

Code:

/event/participant

so

Code:

function parseXML(theXML)
{
  var sXPath = "/event/participant";
  var colParticipant = theXML.selectNodes(sXPath);
  alert("Participant count: " + colParticipant.length);
  for (var i = 0; i < colParticipant.length; i++)
  {
    var oParticipant = colParticipant[i];
    var oFirstname = oParticipant.selectNodes("firstname")[0];
    var oLastname = oParticipant.selectNodes("lastname")[0];
    alert(oFirstname.childNodes[0].nodeValue + " " + oLastname.childNodes[0].nodeValue);
  }  
}

Thre are hundreds of tutorials on XPath, try W3Schools for starters.

--

Joe (Microsoft MVP - XML)

rvanandel · August 29th, 2005, 09:37 AM

Thank you, this is exactly what I needed.