Update store.overflow.js

So in my IE9 the overflow functions werent working.
I checked why. And came to the conclusion that e.name is undefined in IE9.
But i found out that e.toString() gives nevertheless the string to compare it.
And i just read that ie10 will return "QuotaExceededError".

See: http://msdn.microsoft.com/en-us/library/ie/gg592979(v=vs.85).aspx