Question

I am writing a XML file into a HTML file using JavaScript.

Here is the JavaScript I am using:

if(window.XMLHttpRequest){
   xmlhttp=new XMLHttpRequest();
}
else{
   xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET","file.xml",false);
xmlhttp.send();
xmlDoc=xmlhttp.responseXML; 

var x=xmlDoc.getElementsByTagName("tagParent");

document.write(x.getElementsByTagName("tagChild")[0].childNodes[0].nodeValue);

The script will working for everything except for self closing xml elements (<element/>).

Example XML file:

<?xml version="1.0" encoding="ISO-8859-1"?>
<tagParent>
    <tagChild/>
</tagParent>

The script breaks and stops when it reaches a self closing tag.

What do I need to do to get it either output 0 or “”? Why is it breaking?

Answer 1

It is breaking because the element is empty. It doesn’t have any children so when you try to get the nodeValue of the first child, it errors because undefined doesn’t have a 0 property.

You want something along the lines of:

var dataNodes, value;
dataNodes = x.getElementsByTagName("tagChild")[0].childNodes;
if (dataNodes.length) {
    value = dataNodes[0].nodeValue;
} else {
    value = 0;
}
document.write(value);