XSSQL attack (HTML5)
It is pretty clear that many developers would use the opportunity to store information on the client side. The risk will be high if they use this repository and store there sensitive information such us user passwords, session ids, credit card numbers etc.
I even have a name for this attack – XSSQL funny as well as concerning …
Eventually, XSS attacks still remain common and even more powerful with the ability to query client side databases and steal sensitive information.
See more details at http://yossi-yakubov.blogspot.com/2011/07/html-5-xssql.html