I have the following XML file:
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!-- Edited by XMLSpy® -->
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
And using the following Javascript/HTML:
<html>
<body>
<h1>W3Schools Internal Note</h1>
<div>
<b>To:</b>
<span id="to"></span>
<br />
<b>From:</b>
<span id="from"></span>
<br />
<b>Message:</b>
<span id="message"></span>
</div>
<script type="text/javascript">
if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest();
} else { // code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET", "note.xml", false);
xmlhttp.send();
xmlDoc = xmlhttp.responseXML;
document.getElementById("to").innerHTML = xmlDoc.getElementsByTagName("to")[0].childNodes[0].nodeValue;
document.getElementById("from").innerHTML = xmlDoc.getElementsByTagName("from")[0].childNodes[0].nodeValue;
document.getElementById("message").innerHTML = xmlDoc.getElementsByTagName("body")[0].childNodes[0].nodeValue;
</script>
</body>
</html>
This is working fine, but if one of the values in the XML file has no value such as <from></from> then the rest of the values will not return any data.
Any ideas how I can detect this and move on, even if there is no value in the node?
It’s because when the tag has no value, it has no child node, specifically a text node. This makes
childNodecontain nothing, andchildNode[0]isundefined. If you try to get a property of anundefined, it will run into an error:Here’s a sample using a blank
<span>