I actually touch on the differences between nodeLists and arrays several times on the site, most recently in this post on getElementsByClassName

getElementsByTagName doesn't return an array. It's an "array-like" collection of HTML elements. If you do this:

alert(document.getElementsByTagName('p'));

in Mozilla, you will be told "[object HTMLCollection]" since that is what it is. In more friendly-speak, it's known as a node list, but it is NOT an array. For example, the Array object's concat method won't work on it because it isn't an array. However, you can loop through it and it has a length property, which is why it is often confused with an array.

Do you have any idea about handling null values which are passed to getElementsByTagName().

For example

var obj = xmlDoc.getElementsByTagName("x")[0];

var objerrorcode = obj.getElementsByTagName("y")[0];

where in xml , x is the parent of y. and y has some childNodes. if the complete tag ( somestuff ) itself is not passed , how can you handle this when y has some childNodes which have to be accessed ?

xml_document.getElementsByTagName("city") [0].id;

or

xml_document.getElementsByTagName("city") [0].getAttribute("id");

i put the id property to identify the contract,
when i handle the response i get the inner text 'Test Contract' with no problem, but how can i access the 'id' property?

thanks,
orlando

At that point you've got a reference to the object and can do whatever you want with it.

Need help!
No body explain how to handle element: "[0]"
in javascript.
What it is? 'index' of some kind.
How do I get it and pass it ?
Thanks.
Vladimir

I realize the power of document.getElementsByTagName, which is how I found your page, and I'm trying to use it for a simple page I'm trying to create.

I have three menu options at the top of this page, which I am successfully using CSS to achieve a mouse rollover effect for each selection.

When a user clicks on one of these options, I want to store the <a> tag name into a variable using Javascript.

Here's my feeble attempt:

Demographics
Website Traffic
Rates & Availability

And, here's my feeble attempt at creating a Javascript function–GetTg() to store the a tag reference to a variable name using document.getElementsByTagName.

function GetTg() {
var TgVar = document.getElementsByTagName('a');
}

Once I can store the anchor tag to a variable, I want to use it in a switch/case statement to display HTML based on the selection.

Any help is appreciated…