Syntax Error? When parsing XML value

Question

I don't know if I'm having a syntax error but the compiler is giving me

TypeError: 'undefined' is not an object (evaluating 'xmlDoc.getElementsByTagName("icon")[count].childNodes')

Its me giving me this problem when im parsing the XML from my server, my actual javascript code is like this

var xmlDoc = Obj.responseXML;
var count = 0;
if(xmlDoc){
    while(count <= xmlDoc.getElementsByTagName("item").length){
    document.getElementById("flow").innerHTML += "<div class='item'><img class='content' src='" + xmlDoc.getElementsByTagName("icon")[count].childNodes[0].nodeValue.replace(/\s+$/g,' ') +"' /></div>";
    count++;
    }
       }else{
           alert("Unable to parse!");
       }

and my XML goes like this.

<feed>
<item>
<title>Given Title</title>
<icon>
http://i178.photobucket.com/albums/w255/ace003_album/Logo-ETC-RGB-e1353503652739.jpg
</icon>
</item>
<item>...</item>
<item>...</item>
<item>...</item>
<item>...</item>
<item>...</item>
<item>...</item>
</feed>

i just want to parse the image link and to show it. DOM parser

 var url = "http://myURL.com/document.xml";
        if (window.XMLHttpRequest)
          {// code for IE7+, Firefox, Chrome, Opera, Safari
          Obj = new XMLHttpRequest();
          }
        else
          {
          Obj = new ActiveXObject("Microsoft.XMLHTTP");
          }

        Obj.open("POST",url,false);
        Obj.setRequestHeader("Content-type","application/x-www-form-urlencoded");
        Obj.send();

check what i is, what is probably happening is you are trying to access an icon element that doesn't exist in the node list. — scrappedcola
– scrappedcola, Commented Oct 25, 2013 at 15:51
@Ace Munim Give a look js-xpath.sourceforge.net/xpath-example.html and npmjs.org/package/xpath — HILARUDEEN S ALLAUDEEN
– HILARUDEEN S ALLAUDEEN, Commented Oct 25, 2013 at 16:38

MrCode · Accepted Answer · 2013-10-25 16:30:32Z

1

Demo

Firstly, you're while loop condition should be just < not <=. By using the latter, the loop is running one too many times, causing the error because the index is out of bounds.

Secondly, in the while loop you're getting the icon elements based on the count from the root of the document. The icon's are children of each item so you should retrieve the icon relative to the item by using item.getElementsByTagName('icon')[0] not xmlDoc.getElementsByTagName('icon')[count].

Not related to the problem but building HTML as strings like that is undesirable. Creating the elements and inserting them into the DOM would be better because you don't need to handle any escaping. Also, store a reference to flow before the while, instead of finding it on each iteration.

var div;
var img;
var flow = document.getElementById('flow');
var items = xmlDoc.getElementsByTagName("item");

while(count < items.length){
    div = document.createElement('div');
    div.className = 'item';

    img = document.createElement('img');
    img.className = 'content';
    img.src = items[count].getElementsByTagName("icon")[0].childNodes[0].nodeValue.replace(/\s+$/g,' ');

    div.appendChild(img);
    flow.appendChild(div);
    count++;
}

edited Oct 25, 2013 at 16:30

answered Oct 25, 2013 at 15:52

MrCode

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4 Comments

Ace Munim Over a year ago

i did change and all, and sorry the variable i with count was a typo, and also I've implemented the method you told me as it is much better in creating element. But still im having the same error. Is there any way to check whether I'm getting the proper XML?

Ace Munim Over a year ago

yup it is, added the DOM parser in the question.

Ace Munim Over a year ago

im getting the full XML from my site with the Obj.responseXML

MrCode Over a year ago

See my edit. There's a couple of problems. Also see the demo (you don't need the DOMParser that I have in the fiddle but it's needed for the demo).

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