Got the same issue, works in IE.

Happening to me too. No settings changed, nothing added. Just stopped working on eBay alone (as far as I can tell) No problem with same pages on Opera or Camino.

Problem is with Firefox and I'm really not happy with number of niggling problems I seem to be having with it these days......

Javascript is not working at all for me on any website. I'm on OSX. It happened after I installed then uninstalled the torbutton extension. I even tried upgrading to Firefox 4 to see if that would help. This made no difference.

Problem still exists in Firefox 5.0 and OSX 10.6.8 It was a fresh install of Firefox 5.0 so no extensions. And Javascript IS enabled in preferences.

Sites work fine in Safari.