Strange. v20130808 looks to be the date. Something suspicious about today's chess.com javascript? These virus scanners tend to have pretty tight nets, so it might be a false positive. I'd err on the side of caution.
Malware detected
Sort:
ClamAV shows it as clean. I downloaded it and scanned it. These were the results.
$ clamscan ChessViewer.v20130808.js
ChessViewer.v20130808.js: OK
----------- SCAN SUMMARY -----------
Known viruses: 2555112
Engine version: 0.97.8
Scanned directories: 0
Scanned files: 1
Infected files: 0
Data scanned: 0.59 MB
Data read: 0.25 MB (ratio 2.36:1)
Time: 20.901 sec (0 m 20 s)
Your mileage may vary.
Today at 7:42:40 ET I tried to log into my currect game, whereupon my AVG antivirus program blocked me with the message that it has detected "Exploit Rogue Scanner (type 831) Severity High at cssjs.chesscomfiles.com/js/chess2/bundled/ChessViewer.v20130808.js"