JAX can be used for interactive communication with an XML file.
The following example will demonstrate how a web page can fetch information from an XML file with AJAX:
When a user selects a CD in the dropdown list above, a function called "showCD()" is executed. The function is triggered by the "onchange" event:
<html>
<head>
<script>
function showCD(str) {
   if (str=="") {
     document.getElementById("txtHint").innerHTML="";
     return;
   } 
   var xmlhttp=new XMLHttpRequest();
   xmlhttp.onreadystatechange=function() {
     if (this.readyState==4 && this.status==200) {
       document.getElementById("txtHint").innerHTML=this.responseText;
     }
   }
   xmlhttp.open("GET","getcd.php?q="+str,true);
   xmlhttp.send();
 }
</script>
</head>
<body>
<form>
Select a CD:
<select name="cds" onchange="showCD(this.value)">
  <option value="">Select a CD:</option>
  <option value="Bob Dylan">Bob Dylan</option>
  <option value="Bee Gees">Bee Gees</option>
  <option value="Cat Stevens">Cat Stevens</option>
</select>
</form>
<div id="txtHint"><b>CD info will be listed here...</b></div>
</body>
</html>
The showCD() function does the following:
The page on the server called by the JavaScript above is a PHP file called "getcd.php".
The PHP script loads an XML document, "cd_catalog.xml", runs a query against the XML file, and returns the result as HTML:
<?php
$q=$_GET["q"];
 
$xmlDoc = new DOMDocument();
$xmlDoc->load("cd_catalog.xml");
 
$x=$xmlDoc->getElementsByTagName('ARTIST');
 
for ($i=0; $i<=$x->length-1; $i++) {
   //Process only element nodes
   if ($x->item($i)->nodeType==1) {
     if ($x->item($i)->childNodes->item(0)->nodeValue == $q) {
       $y=($x->item($i)->parentNode);
     }
   }
 }
 
$cd=($y->childNodes);
 
for ($i=0;$i<$cd->length;$i++) { 
   //Process only element nodes
   if ($cd->item($i)->nodeType==1) {
     echo("<b>" . $cd->item($i)->nodeName . ":</b> ");
     echo($cd->item($i)->childNodes->item(0)->nodeValue);
     echo("<br>");
   }
 }
?>
When the CD query is sent from the JavaScript to the PHP page, the following happens: