Here's my problem:

I have groups of elements that are scattered around my page but have identical id's so that I can reference them all at once (as a group).

These elements are sitting inside of an iFrame, that is sitting inside another iFrame (that is building a nested navigation bar).

So what I want to do is have a script sitting in the top document that when a button is pressed it will reference those double-nested identical id's and toggle their display.

and this is what I have so far...
(while testing, I do not have any identical id's)
HTML Code:
<!-- my buttons -->
<form>
	<input type="checkbox" name="DTS" onclick="toggleFilter(\'DTS\', this.checked);" checked /> Toggle DTS Numbers |
	<input type="checkbox" name="DCS" onclick="toggleFilter(\'DCS\', this.checked);" checked /> Toggle DCS Numbers |
	<input type="checkbox" name="IGT" onclick="toggleFilter(\'IGT\', this.checked);" checked /> Toggle IGT Numbers
</form>

<!-- my script -->
<script type="text/javascript">
<!--
	
	function toggleFilter(myElement, myChecked)
	{
		alert("toggleFilter("+ myElement +","+ myChecked +")");
		
		var toggle =(myChecked == true)? "block" : "none";
		alert("toggle = "+ toggle);
		
		var myDIV = document.frames["parentFrame"].document.frames["bodyFrame"].document.getElementById("272");
		alert("myDIV = "+ myDIV);
		
		myDIV.style.display = toggle;
		
		alert(myDIV +".style.display = "+ toggle);
	}
	
 -->
</script>
Now, as you can see, I have alert boxes tracing debug information for me. So when I hit the check boxes, both the 1st and 2nd alert box trigger, but the 3rd does not, so I know the error is hitting at myDIV's definition.

I looked at a bunch of sites and this was the best I could devise for how to do it, but it's obviously not working.

Any advise?