The line at the top of the page, for me, says "Undefined".
Firefox 10.0.7, Windows 7.
I debugged it for you - the outerHTML property isn't supported in Firefox < 11. Here's the solution from StackOverflow:
function outerHTML(node){ return node.outerHTML || ( function(n){ var div = document.createElement('div'), h; div.appendChild( n.cloneNode(true) ); h = div.innerHTML; div = null; return h; })(node); }