It may have to do with the JotFormIFrame
code that you have embedded.
The HTML for it looks like this right now, on your page:
<iframe id="JotFormIFrame" onload="window.parent.scrollTo(0,0)" allowtransparency="true" src="http://form.jotform.us/form/41198414446154" frameborder="0" style="width: 100%; height: 692px; border: none;" scrolling="no"></iframe>
And as far as I can tell, that will scroll the page back to the top as soon as the iframe has loaded (this will happen whether there is an id in the URL or not, although if there isn't, then scrolling to the top doesn't do anything).
I don't know why it wouldn't do the same thing in other browsers; there may be a difference in the timing of events, or it may be that Firefox, etc, don't allow the iframe to scroll the parent window.