When eBay started implementing Webslices, they did in a special search page ie8.ebay.com. They removed that page a few months ago because they moved the feature to the normal eBay pages. But this has a bad, and I hope involuntary, side effect : Webslices work now only with MSIE and not with Firefox+Webchunks any more. There is something, on the server- or client-side that does client-sniffing probably based on the MSIE extensions to window.external, and eBay result pages are different between MSIE and other browsers.

In MSIE8, all result entries in eBay have a hslice class and a related ID to be detected as a webslice by MSIE8.

eBay in MSIE8 Developer Tools
eBay in MSIE8 Developer Tools

In Firefox, the very same page does not have the hslice class. The ID, required by the Webslices spec, is dropped to.

same page in Firefox Document Inspector
same page in Firefox Document Inspector

Again, I have no idea if this is made on purpose or not. If it is, it's a true scandal. If it's not, and given the fact the Webchunks extension to Firefox is freely available, it's a shame. Please note that the embedded JavaScript shows no error or related warning... Please also note that if you use a UAString-switcher in Firefox, the result remains the same; that's why I think the client-sniffing is client-side and based on window.external.* MSIE extensions. I hope that eBay is going to fix this as soon as possible, because banning Firefox users seems to me a stupid and counter-productive idea...