function ShowHide(ElementID, ID)
{
$(ElementID).style.display = ($(ElementID).style.display == 'none' ? '' : 'none');
$(ElementID).src.value = 'http://www.somewebsite.com/somedir/' + ID;
}

I get a Javascript error saying '$ is not defined'. I can't remember what $(...) is called in DOM but I know it references id="..." elements. I can't figure out what is wrong on my own because Google doesn't search for characters like '$'. The code looks like:

<h2><a href="#" onclick="ShowHide('orig', 2);">ID #2</a>:</h2>
<iframe id="orig" style="display: none;" src="" width="80%" height="400"></iframe>