I'm writing an AJAX application that retrieves a dynamically created XML file from a webserver (the xml is created using PHP). I've got the application working great except when the field is empty. In particular, the following XML

<?xml version="1">
<data>
  <date>1/2/2005</date>
  <time></time>
  <event>Something is happening</event>
</data>

As you can see, the time field is empty and when I run the javascript to parse the returned data, I get a javascript error.

I'm using the following javascript to parse the file
function parseXML() {
  var theXML = xmlHttpReq.responseXML;
  var date= theXML.getElementsByTagName('date')[0].firstChild.data;
  var time = theXML.getElementsByTagName('time')[0].firstChild.data;
  var event = theXML.getElementsByTagName('event')[0].firstChild.data;

}

The error happens when I try to assign the value to the time variable. The firefox javascript console tells me that firstChild has no properties.

My question: how do I check to see if there is data present? I've tried several different things like
if(typeof(theXML.getElementsByTagName('time')[0].firstChild) != "undefined")
But it's just not working.

Thanks for your help.

Try this:

if( theXML.getElementsByTagName('time')[0].firstChild ){
    var time = theXML.getElementsByTagName('time')[0].firstChild.data;
}