Nice find. I've been foraying into where these strange xpopup.js errors filling my web server logs have been coming from for awhile now...

I've run into too many cases over the years in which web-browsing computers' security software made strange presumptions in tinkering with incoming web pages' HTML. All too often, those presumptuous tinkerings result in breakages in some cases or others, and the "secured" web-browsing users (and the web developers to which they complain) are left wondering why stuff doesn't work right.

sigh

Thanks.