PHP - AJAX XML Parser

Using PHP with AJAX, we can parse an XML document from local directory as well as on a server. The following example demonstrates how to parse XML with web browser.

The client-end script renders a HTML form and defines a JavaScript function for sending a HTTP request to the server with XMLHttpRequest object.

On the server, a PHP script loads the DOM object from the required XML document, fetches the selected course from $_REQUEST variable, and renders the details of the course chosen as the response back to the client.

Step 1

The following XML document is stored on the document root of the XAMPP server.

<?xml version = "1.0" encoding = "utf-8"?>
<CATALOG>

   <SUBJECT>
      <COURSE>Android</COURSE>
      <COUNTRY>India</COUNTRY>
      <COMPANY>TutorialsPoint</COMPANY>
      <PRICE>$10</PRICE>
      <YEAR>2015</YEAR>
   </SUBJECT>

   <SUBJECT>
      <COURSE>Html</COURSE>
      <COUNTRY>India</COUNTRY>
      <COMPANY>TutorialsPoint</COMPANY>
      <PRICE>$15</PRICE>
      <YEAR>2015</YEAR>
   </SUBJECT>

   <SUBJECT>
      <COURSE>Java</COURSE>
      <COUNTRY>India</COUNTRY>
      <COMPANY>TutorialsPoint</COMPANY>
      <PRICE>$20</PRICE>
      <YEAR>2015</YEAR>
   </SUBJECT>

   <SUBJECT>
      <COURSE>Microsoft</COURSE>
      <COUNTRY>India</COUNTRY>
      <COMPANY>TutorialsPoint</COMPANY>
      <PRICE>$25</PRICE>
      <YEAR>2015</YEAR>
   </SUBJECT>
   
</CATALOG>

Step 2

The AJAX code below has a HTML form and a JavaScript function to raise HTTP request through XMLHttpRequest object.

<html>
<head>
   <script>
      function showCD(str) {
         if (str == "") {
            document.getElementById("txtHint").innerHTML = "";
            return;
         }

         if (window.XMLHttpRequest) {
		 
            // code for IE7+, Firefox, Chrome, Opera, Safari
            xmlhttp = new XMLHttpRequest();
         } else {  
		 
            // code for IE6, IE5
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
         }

         xmlhttp.onreadystatechange = function() {
            if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
               document.getElementById("txtHint").innerHTML = xmlhttp.responseText;
            }
         }
         xmlhttp.open("GET","hello.php?q="+str,true);
         xmlhttp.send();
      }
   </script>
</head>
<body>
   <form>
      Select a Course:
      <select name = "cds" onchange = "showCD(this.value)">
         <option value = "">Select a course:</option>
         <option value = "Android">Android </option>
         <option value = "Html">HTML</option>
         <option value = "Java">Java</option>
         <option value = "Microsoft">MS technologies</option>
      </select>
   </form>
   <div id = "txtHint"><b>Course info will be listed here...</b></div>
</body>
</html>

Step 3

The server-side PHP script to search within the XML document is as follows −

<?php
   $q = $_GET["q"];

   $xmlDoc = new DOMDocument();
   $xmlDoc->load("test.xml");

   $x = $xmlDoc->getElementsByTagName('COURSE');

   for ($i = 0; $i<=$x->length-1; $i++) {
      if ($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++) {
      if ($cd->item($i)->nodeType == 1) {
         echo("<b>" . $cd->item($i)->nodeName . ":</b> ");
         echo($cd->item($i)->childNodes->item(0)->nodeValue);
         echo("<br>");
      }
   }
?>

Visit "http://localhost/example.php" to let the user select a course. Upon selection, the relevant details are fetched from the server and displayed as below −

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