If I have <element1> which is somewhere within my XHTML document, and element one has a shit-ton of child nodes, and I call:

var children = element1.getElementsByTagName('a');

Then children will be an array containing element pointers/objects for all of the 'a' tags within <element1>, but nowhere else on the page.  Right?

Mat's not there to tell you to read the specs... :)

http://developer.mozilla.org/en/docs/DOM:element.getElementsByTagName

:-P

Yeah, seriously, isn't there a manual for this.

The answer is yes.  It's limited to children of that element.

I think it's better if you have check if the length is greater than 0. I've had runtime errors because of not doing it.

OK so why when I run this:

var links = document.getElementById('lithCore_ThreadList').getElementsByTagName('a');

Am I only getting the first anchor element, and none of the subsequent ones?  'lithCore_Threadlist' contains one hundred anchor tags.

the reason I say I'm only getting the first element is that when I run this:

for (i = 0;i < links.length; i++) {
  alert(links[i].id);
}

I only get one alert box, with the ID of the first anchor tag.

I sort of remember having such an issue but I can't recollect right now  to what was causing it. Did you try giving it in two separate statements the way it's given in the above link?

When I do this:

var threadDiv = document.getElementById('lithCore_ThreadList');
var links = threadDiv.getElementsByTagName('a');

I get NONE of the anchor tags in lithCore_ThreadList

Clearly I'm doing something wrong, but what?!

In case anybody cares, the relevant URL:

http://www.madebymonkeys.net/?template=lithCore_Index

The problem javascript is in the top frame, in getCurrentThreads().

Do the anchor tags have to be DIRECT descendants to show up?

based on this from mozilla, I'd guess 'no':

var table = document.getElementById("forecast-table");
var cells = table.getElementsByTagName("td");

Are you sure you're getting the ID for the *first* link and not some other link?  I know it sounds like a stupid question, but you never know.

Right now I'm not getting ANY ids.

What did you break?

I switched my original line with chained method calls to two lines.

I'm getting the links.length as 100 here. I'm using IE. If it's FF you are using I think we should check the differences for the browsers.

Original:

var links = document.getElementById('lithCore_ThreadList').getElementsByTagName('a');


New:

var threadDiv = document.getElementById('lithCore_ThreadList');
var links = threadDiv.getElementsByTagName('a');

First one gives me some ID, which I assumed was the first <a> tag.

Second one gives me bupkis.

SNS -

Weird, man.  Maybe it's my work proxy foiling me.

I took the code from mozilla.org, so you'd think it'd be fine for FF.

"First one gives me some ID, which I assumed was the first <a> tag."

Find out for sure...  if it's not the first ID then I have a theory.  If it is, then I don't.  ;)

Can't be my work proxy, the javascript isn't getting rewritten at all.

I'm stumped.

I added an alert for links.length.  I downloaded FF's Javascript debugger but the interface has me flummoxed.

I get a msgbox that says 100 in Firefox as well.

Also, the 'onLoad' event on the footer div seems never to fire.  But that's another issue.  :-)

I got '100' in my msgbox just now.

Ok the problem is elsewhere.

Garrrrrr.

Earlier I had the alert in the loop that iterates through 'links', and I only ever got ONE msgbox.

Like right now.

The loop only seems to iterate once.

The ID that comes up IS the id of the first <a> tag.

I think I know why...

Nope, I don't.

Fuck.

Mup, although this doesn't help you with your actual problem (which I'm too tired to think about at the moment) it's probably worth modifying your code to make sure it IS looking at the right links -- basing anything on the assumption that what works "by chance" now will always work is the way to an early grave. :)

Think I've got it.

The links.length gets displayed fine.

alert(links[i].id);
var index = links[i].id;
updatedIDs[index] = true;
if (messageIDs[index] != true) {
      newMessages.push(index);
}

The above code displays the alert only once and it is the ID of the first 'a' tag.


alert(links[i].id);
/*var index = links[i].id;
updatedIDs[index] = true;
if (messageIDs[index] != true) {
      newMessages.push(index);
}*/

After commenting the way above I get the subsequent alerts and they too are the correct IDs.

Yeah, the trouble was that I need to initialize variables as Arrays explicitly in javascript, and I didn't know that.

Every other script language I use has autovivification.  :-)

Thanks for your help.  Seriously.

Most welcome.

I was bored and it was good diversion to think about this...