How to get parent iframe element from inner page w

Let's imagine that I have something like this:

<html>
...
    <div>
        <iframe src="test.html" hash="r4d5f7"></iframe>
        <iframe src="test.html" hash="8f7x97"></iframe>
        <iframe src="test.html" hash="gg4v5e"></iframe>
        <iframe src="test.html" hash="e54f87"></iframe>
    </div>
...
</html>

test.html is empty page, custom hash attribute always has a different value, both pages are on the same domain for security reasons, number and order of iframe elements is random.

My question is: Is there a way to get from inner page (test.html) using Javascript to its proper iframe element? Let's say, I'm in the third iframe's page and I need to get to its iframe element and alert() hash value (in this case "gg4v5e").

To be more specific. If you are familiar with Firefox's Firebug, it visualizes this situation like this:

<html>
...
    <div>
        <iframe src="test.html" hash="r4d5f7">
            <html>
                 ...
            </html>
        </iframe>
        <iframe src="test.html" hash="8f7x97">
            <html>
                 ...
            </html>
        </iframe>
        <iframe src="test.html" hash="gg4v5e">
            <html>
                 ...
            </html>
        </iframe>
        <iframe src="test.html" hash="e54f87">
            <html>
                 ...
            </html>
        </iframe>
    </div>
...
</html>

Is it possible to call "something" in order to get parent element (<iframe>) when I'm with my Javascript at <html> element in inner page?

Sure there is. This code works in FF and IE6, Opera, Chrome (requires a web server and both files coming from same domain protocol and port)

        function getHash()   {
           var ifs = window.top.document.getElementsByTagName("iframe");
           for(var i = 0, len = ifs.length; i < len; i++)  {
              var f = ifs[i];
              var fDoc = f.contentDocument || f.contentWindow.document;
              if(fDoc === document)   {
                 alert(f.getAttribute("hash"));
              }
           }
        }